HALOT gives two definitions, the first being song and the second being strength:
I זִמְרָה: I זמר; MHb. זמר, MHb.2 זימרה; Sam. זמר (Ben-H. 2:490,
546); CPArm. zmrʾ; Mnd. MdD 159b זאמרא; Akk. zimru: melody, sound (of
an instrument) Is 51:3 Am 5:23 Ps 81:3 (with נשׂא to make resound)
98:5; praise (|| קול) 11QPsa (DJD 4, p. 64, 11). †
II זִמְרָה: III זמר: זִמְרָת Ex 15:2 Is 12:2 and Ps 118:14 (before
י, rd. זִמְרָתִי, 1QIsa; BL 603g; Talmon VT 4:206ff): strength Ex 15:2
(:: protection Gaster ExpT 49:189) Is 12:2 Ps 118:14 (→ III זמר);
זִמְרַת הָאָרֶץ strength (i.e. the best products) of the land Gn
Koehler, L., Baumgartner, W., Richardson, M. E. J., & Stamm, J. J. (1994–2000). The Hebrew and Aramaic lexicon of the Old Testament (electronic ed., p. 274). Leiden: E.J. Brill.
One unambiguous place where it cannot mean "song" would be Gen 43.11: "the best (zimrat) products of the land". In all other situations, you can replace it with song.
The idiom (ozzi v zimrat) is used in Ex 15:2, Is 12:2 and Ps 118:14.
Most translations use "song", but there are academic translations that don't. E.g. Hermeneia reads
Behold the God of my salvation!
I will trust and not be afraid,
For my strength and my might are Yah,
And he has become my salvation.
Roberts, J. J. M. (2015). First Isaiah: A Commentary. (P. Machinist, Ed.) (p. 191). Minneapolis, MN: Fortress Press.
The Lexham English Bible has:
Look! God is my salvation; I will trust, and I will not be afraid, for
my strength and might is Yah, Yahweh; and he has become salvation for
The JPS Tanakh also has "might"
For Yah the LORD is my strength and might,
Jewish Publication Society. (1985). Tanakh: The Holy Scriptures (Is 12:2). Philadelphia: Jewish Publication Society.
KJV/RSV/NRSV use the more popular "song"