Parashas Chayei Sarah · Passuk 24:17
The servant ran toward her and said, “Please, let me sip a little water from your jar.”
Torah Temimah points to Shabbos 77a. E-Daf · Sefaria — Shabbos 77a
TT lemma: הגמיאיני.
From here [we learn] that the measure for carrying liquids on Shabbos is “enough for a sip (gemiah)” with an alef, as in Eliezer’s request.
Custom (Bavli — precise measure for carrying liquids on Shabbos)
The minimum quantity of liquid that creates liability for carrying on Shabbos is the amount of a “sip,” as fixed by the language of Eliezer’s request.