When I was in eighth grade, I asked a rabbi a question. If we believe in only one God, why is God’s name in Hebrew a plural? I know I was thinking of the name Elohim אלו-הים, but I might have also been thinking of Adonai אדנ-י (which would seem to mean "my Lords"). I don’t believe the rabbi ever directly answered me, but did say something like, “Now that’s a good question.” My understanding at the time was that there was some significant theological significance to the plural forms. In more recent years, I would have assumed that some secular biblical scholars might attribute the plural forms to a polytheistic origin of the Israelite religion.
But due to a question a friend recently asked me, I’ve realized that the plural form doesn’t necessarily say much about the nature of God at all. She asked why is it that a husband (in Hebrew) is a baal בעל, but the (single) owner (of a pet, or a company) is called baalim בעלים. (We've seen the phenomenon of a plural noun being treated as a singular one before, in our discussions about tavlin and Artzot Habrit.) At first I thought this might be a phenomenon only in Modern Hebrew, but I found baalim meaning "owner" a number of times in Biblical Hebrew (e.g. Shemot 21:29, Yishaya 1:3, Kohelet 5:12) and in the Mishna (Bava Metzia 8:1) as well. After digging a little deeper, I found that the same rule applies to the synonym adon אדון. While the singular form (referring to people, not God) is found in the Tanach (also on one occasion meaning “husband”, Bereshit 18:12), it is frequently found in the plural form adonim אדונים, even though that word is used as a singular meaning "lord, master" (see Yishaya 19:4, Malachi 1:6, and the many cases of אדוניך adonecha and אדוניו adonav in the story of Avraham's servant and the story of Yosef. In no place in the Tanach do the words אדונו or אדונך appear.)
Why is this? Both Rav Hirsch in his commentary on Bereshit 1:1 and Shadal in his essay "Tzelem Elohim" (printed in the collection Mechkerei HaYahadut, pg. 225) explain it as showing full sovereignty and authority over the subject (see also Rashi on Bereshit 35:7).
Shadal adds that if adon was written in the singular, you might think that the subject would have this master, and additional masters as well.
Using a plural form to designate a plentitude of powers combined in one person is moreover by no means unusual in expressions of mastery and power in the Hebrew language, such as אדנים, בעלים. They always designate a person who possesses the various powers which rule over any object, to whom, accordingly, this object completely subjected in every direction.
Some people have claimed that because baal means both owner and husband, this implies that in Judaism the husband "owns" his wife. But as we have seen, there are two different words - baalim for owner, and baal for husband.
The case in Hoshea 2:18
וְהָיָה בַיּוֹם-הַהוּא נְאֻם-ה', תִּקְרְאִי אִישִׁי; וְלֹא-תִקְרְאִי-לִי עוֹד, בַּעְלִי
where in the future we will call God ishi אישי instead of baali בעלי (in the analogy of God as the husband and Israel as the wife) is referring to the negative connotations the word baal got from association with the Semitic deity “Ba’al”, as evidenced from the following verse:
וַהֲסִרֹתִי אֶת-שְׁמוֹת הַבְּעָלִים, מִפִּיהָ; וְלֹא-יִזָּכְרוּ עוֹד, בִּשְׁמָם
For I will remove the names of the Baalim from her mouth, and they shall nevermore be mentioned by name.So we should not learn from it the nature of the husband / wife relationship in Judaism, although there are those in Israel who prefer to use "ishi" for husband based on this verse.(For more on ish and isha, see this post.)
In any case, the above principle applies to the title Elohim as well. It too has a few uses in the Bible where it refers to people, although it overwhelmingly is a term used for God. But the plurality here is, as Ibn Ezra says in his commentary on Bereshit 1:1, a “plural of respect” (pluralis excellentiae in Latin). This is similar to the “royal we” (pluralis maiestatis/majestatis in Latin) except that in general we don’t find cases of the sovereign referring to themselves in the plural. (For an excellent review of the meaning and usage of Elohim in the Tanakh, see the chapter “The Knowledge of God” in Man and God: Studies in Biblical Theology, by R’ Eliezer Berkovitz.)
In addition to the definitions “husband” and “owner”, baal is a prefix in compounds meaning “possessing”, as in baal habayit בעל הבית – “landlord, host”, baal kriya בעל קריאה (or the Yiddish influenced, more popular, although less grammatically correct baal koreh בעל קורא) – “the Torah reader” (who possesses the knowledge of how to read), and baal teshuva בעל תשובה – a Jew who has returned to following the laws of the Torah, literally “master of return” (in Israeli Hebrew chozer b’teshuva חוזר בתשובה seems more popular.) However, the phrases baal-peh בעל פה - "orally", and baal-korcho בעל-כרחו - "against his will" do not use our word baal, but rather the letter bet as a prefix followed by the preposition al על.
Yet, while baal had the sense of “possessing” even in Biblical Hebrew, adon was used either to refer to God or a “master” even through Rabbinic Hebrew. Since slavery is no longer practiced, and even political leaders do not have full sovereignty over citizens today, that took the punch out of the second meaning of adon. Today it is almost entirely used to mean "mister" or “sir”. This meaning was lost (either deliberately or not) on the New York Times journalist David Shipler, who wrote in 1984 that Arab cab drivers in Israel refer to Israelis as “My Lord”. As Shmuel Katz (here) and David Bar-Illan (here) pointed out, calling someone “adon” or “adoni” does not necessarily suggest any respect, perhaps actually the opposite…