The headword occurs in Genesis 22:13 LXX, the ram (eventually sacrificed by Abraham in place of his son Issac) caught by its horns in a shrub: κατεχόμενος ἐν φυτῳ̂ σαβεκ τῶν κεράτων . Ancient and modern commentators alike have struggled to understand the word, with some taking it be to the name of the shrub; alternatively, it is construed as some sort of adverbial expansion of katexo/menos; and for 'release' cf. (e.g.) Photius and the Lexica Segueriana.
[1] One manuscript actually adds γλώττης .