The word 'tradition' is derived from Latin 'tradere', i.e. to hand over, deliver, entrust - in its general sense - something from God, Allah through His prophets (upon them be peace).
What is handed over is the Quranic revelation, the āyah (Quranic verses) and - through those - the baraka, divine blessings, which are heavenly powers, all of these leading to sacred knowledge and disinterested action1.
Islam is fundamentally and originally tradition - its timeless, divine message, and this is why the Islamic tradition defines the Islamic religion, not the other way round. They constitute one of the ongoing wonders of Islam.2
In its general meaning, tradition has to be understood in the sense of transmission of an element of the supra-human level, as explained by Sh. `Abd al-Wahīd Yahia.
In its more specific sense the term tradition also signifies the words and sayings reported from the Prophet Muhammad ﷺ may Allah bless him and grant him peace, which have been recorded in the hadith collections.
→ So when speaking of the Islamic Tradition we do not only mean the sayings and words of wisdom by the Prophet of Islam (may Allah’s blessings and peace be upon him - ﷺ, but also the entire Islamic religion (Qur’an, Sunnah, schools of law, spirituality, sanctity, politics, etc.)
Concerning the Arabic expression "al-Dīn al-Qayyim", it is of quranic origin (Sura 10-105; 30-30; 98-5) and signifies the unchanging Religion in its continuing and universal character. Imam Ahmed Vālsan - Presentation (rh)
”To be traditional means to be part of a tradition, and traditions - by their nature - are moving through time and space.” Sh. Abdul Hakim Murad
It is like a tree that grows, constantly changing and evolving, but still connected to the roots and never abandoning those eternal principles. 
Tradition in the sense used here always ”contains an element of a superhuman order.” René Guénon - Shaykh Abd Al Wahid Yahya
“Nothing which is purely human can be considered traditional, ... because only the hereditary forms of an uninterrupted chain of transmission (silsilah) deserve the qualification "traditional" for they will guarantee the reality and permanence of the "vital element", i.e. that of non-human origin, inside a particular tradition.”
René Guénon - Shaykh Abd Al Wahid Yahya, DRG
First of all it is Islam that reigns (see Sura 5:3). Traditional Islam does not accept the notion that the world-religions (and even less so any man-made belief system) would be equally valid paths to God, these are perennialistic interpretations. Even so, they (their laws) still reflect some sacred truth, so they did not turn into falsehood by being abrogated. These 2 (two) different points are to be kept in mind.
In the words of Muhyiddīn Ibn `Arabi:
”The religious laws are all lights, and the law of Muhammad ﷺ among these lights is as the sun's light among the light of the stars…”
”So all paths return to look to the Prophet's path: if the prophetic messengers had been alive in his time, they would have followed him just as their religious laws have followed his law.…”[more]
"When man is imprisoned like this in life and in the conceptions directly connected with it, he can know nothing about what escapes from change, about the transcendent and immutable order, which is that of the universal principles.” RG, East And West, p.90
"In any case, what Westerners call civilization, the others would call barbarity, because it is precisely lacking in the essential, that is to say, a principle of a higher order."
René Guénon, East And West, 1924
More about Shaykh Abd Al Wahid Yahya - René Guénon
Antitradition is the negation of Tradition. In other words, the characteristic symptoms of (post-)modernism, such as materialism, individualism, and secular humanism are a denial of Tradition, in the sense of failing to recognize it; they are a deviation without actually becoming openly hostile. TRT
”When anti-tradition had succeeded in throwing the world into an atmosphere of wide-spread, general materialism, the more inferior forces were able to rise (to the surface). They did this under the the disguise of 'Counter-tradition.'” DRG
”While antitradition is fully in force in the West, and has begun to spread to other parts of the world, we can already see counter-traditional movements rising to the highest echelons of global political, economic, and religious power. The existence of these movements would never be possible without the denial of tradition (i.e. antitradition).” TRT
Anti-tradition and counter-tradition are two important concepts coined by René Guénon [more].
An important aspect of anti-tradition is the ongoing process of the falsification of language, where certain words ”have been diverted from their true, original meaning.” RG
For those who cannot comprehend the meaning of the concept of ’truth’ there is a problem. Postmodernism can posit anything as true, alternatively nothing as really true, or both true at the same time! Or ’true’ is supposedly what has the desired impact!
Does it then surprise that this process has led to today’s mental confusion with many of our contemporaries? But ’human life is characterized by the search for personal or meta meaning.’ NN
Language changes, but not always - not only - at random. Agents of the postmodern deviation are consciously and unconsciously participating in the effort. Words reflect certain meanings and meanings are derived from principles. When principles are lost, which is often the case today, language becomes diluted, even adulterated - and when original meanings are forgotten, concepts will attract new meanings, even meanings in reverse.
One consequence of this is either the arrogance vis-à-vis and unwillingness to understand the classical civilizational texts - ’meta-narratives’, when words appear like skeletons of ancient times, seemingly unknowable meanings from the time they were pinned down.
Another consequence is that one projects one’s own associative thinking upon concepts of Tradition, thereby falsifying the original message of truth.
Also it would be valuable to remind one-self that not everything can be explained exclusively human terms, not everything can be reduced to the human level, and consequently Tradition itself - as we understand it - must not be confused with anything which it is not.
On The Islamic Tradition And The Unchanging Religion, A. Vālsan
Tradition And Traditionalism -- an excerpt (The Reign of Quantity)
Crisis of The Modern World -- Q & A
Crisis of The Modern World -- an excerpt
Oriental Metaphysics; Explanations, And Traditional Definitions
On the Supreme Principle - Metaphysics
True and False Spiritual Teachers
Al-Faqr or 'Spiritual Poverty'
The Fissures In The Great Wall
Signposts: Quotes On Metaphysics, On Non-Dualism etc
Al-Azhar Sufism in Modern Egypt: The Sufi Thought; pt.1 I. M. Abu-Rabi'
Al-Azhar Sufism in Modern Egypt: The Sufi Thought; pt.2 I. M. Abu-Rabi'
A List of Texts On Metaphysics, Tradition, Modernism, re. R. Guénon
Who was René Guénon - Shaykh `Abd Al Wahid Yahya?
On The Significance Of The Teachings of RG For Every Seeker Of Truth
René Guénon's legacy today - From An Interview with Mark Sedgwick
Islamic Tradition Not Equal “Fundamentalism” from S. H. Nasr
What Is Tradition And What Is Traditional About Islam? (short)
Antitradition And Counter-tradition
From Anti-Tradition to Counter-Tradition, Verbatim from:
"The Reign of Quantity and the Signs of the Times"
Metaphysics is the knowledge of the universal principles…
Metaphysics is what is beyond and above nature, therefore it is the one rightly to be called "the Supernatural".
The domain of principles extend much further than some Occidentals have thought, who - nevertheless - have turned metaphysics but into a partial and incomplete mode.
For the metaphysics of the Orient, pure Being is neither the first, nor the most universal of principles, because it is already a determination; it is therefore necessary to go beyond Being - this is after all what is most important.
Quoted from ’La Métaphysique Orientale’, Éditions Traditionelles, Paris 1993
by Shaykh Abd al Wahid Yahya, René Guénon.
Intellect, Reason and Unity Of Being
Eleven (False) New Age Principles
Oriental Metaphysics, Explanations, Definitions, from Réne Guénon
Insights Into The Nature Of (Being) And Existence
Quotes from 'The Sufi Path Of Knowledge; (Ibn al-`Arabi), W. C. Chittick
On the Supreme Principle +That Metaphysics May Not Be Limited, R.G.
Metaphysics - Why Is It Necessary Today? Omar K N
TRT: Former webpage with quotes from RG, now unretrievable.
RG: Shaykh Abd al Wahid Yahya, René Guénon
DRG: Dictionnaire de René Guénon; Jean-Marc Vivenza
1: disinterested action: What is done not following the ego - nafs, but the divine Law, the commandment of Allah (may His Majesty be exalted) and the example of Prophet Muhammad (the blessings and peace of Allah upon him) ↩
2: That despite all the wars, persecutions, the fitna in the world, not only today, but since Islam's inception, and despite the slackening of part of the community and the deviating to extremism by another part of the community; that despite all these problems has the Islamic Tradition kept intact its authenticity, its blessings and its way. ↩
3: Source: What Makes Art Islamic? - YouTube
One Of The Miracles Of Islam | Hamza Yusuf - YouTube
About what is tradition.