Tanmatra is any of the five priordial elements. Tanmatra (That Alone) is that which exists by itself. It is an indivisible unit. It is also called a sukshma bhuta (subtle element).
In the Bhagavad Gita (Chapter VII), Sri Krishna tells Arjuna – ‘This prakrti of mine is eight fold, earth, water, fire, air, space, mind, intellect, and also egoism’.
According to Vedic cosmology the first element to evolve was akasha. From akasha (ether) evolved vayu (air); from air evolved agni (fire); from fire ap (water), and from water prithvi (earth). These are called the subtle elements. They do not mix with one another, and therefore they are called apancikrta (unmixed).
According to Vedanta, the five elements were originally connected with their specific tanmatra. These tanmatras include – Prithvi – gandha tanmatra (smelling), Ap – rasa tanmatra (tasting), Tej – rupa tanmatra (form), Vayu – sparsha tanmatra (touching) and Akasha – sabda tanmatra (sound).
Out of these tanmatras subtle elements are formed the subtle bodies of living creatures. All creatures experience this universe through the five sense organs.