The headword -- probably, given the glossing, extracted from the quotation supplied (see n. 2 below) -- is an epic/ Ionic two-ending adjective in the (masculine and) feminine nominative plural; see generally LSJ s.v. tanumh/khs.
For compounds with tanu-, see also tau 83, tau 85, tau 86, tau 87, and tau 89.
[1] A less literal, but perhaps more veridical, translation of a)/peiron would be indefinite or even great; cf. alpha 3035 (gloss) and alpha 3225 (gloss).
[2] Greek Anthology 6.170.1-2 (web address 1), a dedication (attributed to Thyillos [Thyillus]) to Pan of a spring, its surrounding trees, and some shepherds' water cups; cf. kappa 2735. See further extracts from this epigram at alpha 1740, beta 405, and lambda 483.