The Tocharian B word tsāk
Word tsāk
ts a k
IPA tsak
Meaning illuminate

Comments
Douglas Q. Adams, “Etymological Dictionary of Tocharian B”, 1999, Brill

Other words that might be of interest
kauṃ ‘sun’, pūwar ‘fire’, taur ‘ash, dust’, läkutsetstse ‘bright’, pälk- ‘burn’, pälśalñe ‘burning’, wärs-2 ‘darken’, sleme ‘flame’, parkāsaṃ ‘illumination’, korośāna ‘bright yellow’, yäp- ‘sunset’, skiyo ‘shade, shadow’, pälk ‘shine’