The headword -- similarly glossed in other lexica; evidently quoted from somewhere -- is the third person singular, aorist active indicative, of καθιμάω (see web address 1 for the entry in the LSJ), a compound of ἱμάω and the preposition κατά which here indicates downward motion.
The simple verb means drawing anything by means of a rope or thong (ἱμάς ), especially water from a well. In earlier usage καθιμάω meant to lower something by a rope -- including human beings: cf. Aristophanes, Wasps 396, internet address 2 below. However, in later Greek and certainly by the time of the Suda the verb seems to have developed two distinct meanings: the first having to do with lowering by a rope (see kappa 111) and the other pertaining specifically to the movement of water rather than to the instrumental use of a rope; cf. the second century author Babrius 94.3.
See also iota 331 and iota 359.