The Etymologicum Gudianum glosses kera/meion simply as "earthen vessel, or jar".
[1] The spelling distinction the Suda attempts is ignored by modern editors; LSJ in fact lists "jar" under kera/mion, and the Suda's is the only attested instance of the proper name spelled with iota. The stem was routinely spelled both ways in the manuscript tradition. The proper name is presumably the Ceramic Gulf, a.k.a. Gulf of Keramos, in Karia; accusative *kera/meion ko/lpon in Xenophon, Hellenica 2.1.15.
[2] Phrase also used in tau 432. This may be an interpolation (the phrase is missing from ms F = Laurentianus 55.1), and is probably a cross reference in this entry. The phrase is spelled differently in other attested instances: Oribasius, Eclogae medicamentorum (as keramiai/w| teu/xei); Pollux 10.30 as an illustration of adjectives (teu=xos kerameou=n gh/i+non xutrei=on xalkou=n); Nicander, Theriaca 80 (with scholia) teu=xos keramh/i+on.