On Shabbat, a friend asked me if there was any connection between the word miluim מילואים used in describing the construction and service in the tabernacle (mishkan) and the word miluim used in modern Hebrew for the army reserves.
Well, there certainly is a connection, but it isn't so obvious. Let's take a look.
The word is the gerund form of the root מלא, meaning "to fill" or "to be full", and is only found in the plural. It appears in two separate contexts. The first (Shemot 25:7; 35:9, 27) describe the settings of the stones in the ephod and the breastpiece - אבני מלאים - avnei miluim. Daat Mikra, following Rashi (on 25:7), says that these gems fill the grooves in the gold (or other material), so they are literally "filling stones". The Ramban disagrees, and following Onkelos, focuses on a different sense of the root מלא - "full, complete, perfect". He writes (Chavel translation):
But the sense of the word milu'im is that the stones be whole as they were created, and that they should not be hewn stones which were cut from a large quarry or from anything which has been chipped off. ... This is why Onkelos translated [avnei milu'im - avenei] ashlamutha (stones of perfection).
The other use of milium in the Torah is for the initiaton, inauguration or consecration of the kohanim (priests), as mentioned in Shemot 29:22,26,27,31,34 and Vayikra 7:37;8:22,28,29,31,33. Levine, in the JPS commentary on Vayikra 8:22, where the איל המלאים ail hamilium - "ram of ordination" is discussed, writes:
The Hebrew term millu'im, "ordination," literally means "filling" the hands, a symbolic act that transfers or confers status or office. Further on, in verses 27-29, we read that parts of the offerings were actually placed on the palms of Aaron and his sons, who raised them in a presentation to God. The biblical formula mille' yad, "to fill the hand," is limited to the appointment of priests and cultic officials.We see the connection between filling the hands and milium in Vayikra 8:33 -
In his dictionary, Ben Yehuda writes that in modern Hebrew, the word miluim is used to mean "supplement", again going back to the root meaning "to fill", but here with the sense of "filling in" something. (The Netziv in his commentary to Vayikra 7:37 explains the usage of miluim as "supplement" here as well, as explained in this article). This is a possible origin of the term miluim for the army reserves, as they supplement the soldiers in the standing army.
However, Yaakov Etzion in this article (which discusses many of the points I mentioned above), points out that at the period of the founding of the State of Israel, miluim was synonymous with the older, Talmudic word melai מלאי meaning "merchandise, stock" and was used to mean "reserves" (perhaps this is also related to the meaning Ben Yehuda quoted, but neither he nor Etzion say so). With the founding of the IDF, Ben Gurion called these forces the atudot miluim עתודות מילואים (atudot also meaning "reserves"). But today the two terms have split, with atuda עתודה generally referring to an academic program where the soldier studies in a university prior to his military service in the field of his study, and milium applies to the reserve duty citizens do periodically after they've completed their compulsory army service.
Zuckermann, who feels that the "replacement" of the priestly service in the Temple with military service in the reserves has much more of an ideological motivation than I've described, points out an interesting coincidence. He notes that the mention of the miluim regarding the ordination of the kohanim is found in the parashot of Tzav and Shmini, and that
In Israeli , tsav shmóne ‘Ordinance 8’ is the document informing one of upcoming (often emergency) reserve service, i.e. of miluím. But this is mere serendipity!