small livestock collectively: sheep and goats kept together as a flock, the primary unit of pastoral wealth and sacrifice
Flock (צֹאן) denotes the whole body of small livestock, sheep and goats together, not distinguished from each other: that a herder drives and tends. It appears in contrast to בָּקָר (cattle, large livestock) throughout the biblical narrative, the two together representing the full complement of a wealthy household's animals.
In the patriarchal and pastoral stories, a man's צֹאן is his livelihood: Abel, Jacob, Moses, and David all tend flocks; Laban and Abigail are owners of large flocks; and flock-animals figure prominently in bride-prices, gifts, and treaty negotiations. The breadth of the flock (sheep and goats indiscriminately included) is exactly why the word is so flexible: it names the category, not the species.
In the sacrificial law, the flock supplies the majority of altar animals. Offerings from the flock (מִן הַצֹּאן) include lambs (כֶּבֶשׂ) and goats (עֵז), and the regulations for burnt offerings, peace offerings, sin offerings, and guilt offerings all specify categories from the flock alongside those from the herd. The tithe of the flock (Lev 27:32) and the firstborn of the flock (Deut 15:19) are required as YHWH's portion, placing the animal itself within Israel's covenant obligations.
The word also describes the sheer scale of national wealth in census and tribute contexts: tens of thousands of sheep and goats plundered in battle, presented as gifts to kings, or counted among a household's assets. Here צֹאן functions as a collective mass noun for small livestock viewed as property.