Answer

Tejas-kāya in Jain Dharma means fire-bodied beings. In the Jain classification of life, it is the third of the six jīva-kāyas: earth-bodied, water-bodied, fire-bodied, air-bodied, vegetation-bodied, and mobile beings. Jain reference works explain it this way, and they also distinguish it from the separate term taijasa śarīra (the subtle “fiery body”). ( jainqq.org)

Explanation

In simple language:

• Tejas = fire
• Kāya = body, or a body-group

So tejas-kāya means beings whose body is of the fire category. Explanatory Jain texts give examples such as flame, lightning, and other forms of fire. The spiritual meaning is important: Jainism extends ahiṃsā to very subtle forms of life, not only to animals and humans. ( jainqq.org)

Scriptural locations

The doctrine of the six jīva-kāyas is referred to in the Ācārāṅga tradition and in the Sūtrakṛtāṅga. The Uttarādhyayana Sūtra contains a verse about rebirth in the tejas-kāya genus. The Prajñāpanā / Pannavaṇā Sūtra is also a major scripture for this kind of classification, and later Jain explanatory works like Jīva-Vicāra discuss tejas-kāya in more detail. ( jainqq.org)

Takeaway

So, tejas-kāya means fire-bodied life in Jain scripture. Its deeper purpose is to remind us that Jain non-violence covers even subtle forms of living beings. ( jainqq.org)