Exodus 16:36

36. An omer The reason for here specially mentioning the capacity of the omer seems to be that given by Michaelis and Hengstenberg . Literally, the word omer signifies a sheaf of wheat, but in this chapter it denotes a measure, and it is never used with this meaning afterwards . When subsequently the same measure is spoken of it is called the tenth part of an ephah, as in Numbers 5:15; Numbers 28:15. According to these commentators the word here really means the little earthen vessel or cup which the Israelites used for drinking purposes in the desert, and the author here means to say that this cup usually held a tenth of an ephah, the ephah being then a well known measure. In arranging the book into regular form for the use of coming generations it was proper and appropriate thus to describe the capacity of the vessel in which the Israelites measured the daily allowance of manna. Afterwards the name of the vessel came naturally to be used to designate the measure of the vessel as our word “cup” has both meanings, the vessel and the measure. Omer is to be distinguished from homer, which was ten ephahs, or a hundred omers.