Abarim Publications' online Biblical Hebrew Dictionary
לג
The masculine noun לג (log) is a measure of volume, and not a very big one. Twelve times one log resulted in one hin, and six times a hin went into one bat, which is estimated to be about 22 liters, and that would make the log about 1/3 liter; a little under a pint.
The לג (log) is mentioned only in Leviticus 14:10-24, which deals with the procedure of the cleansing of lepers, and only as a measure of oil (שמן, shemen). It's possible that this word was used as a proverbially small measure, although there is no textual evidence for this.