Also see definition of "Pair" in Word Study
Study Dictionary
Pair
PAIR [ISBE]
PAIR - par: The margin of Song 4:2 (but not of the parallel 6:6) reads, "which are all of them in pairs," while the text has, "whereof every one hath twins." The Hebrew math'imoth, is from the root, ta'am, "to be double," and is perhaps susceptible of either meaning. But the description is of sheep, and the margin gives no comprehensible figure, while the text points to the exceedingly sleek and healthy appearance. "Pairs" seems to result from confusing the figure with the thing figured--the teeth, where each upper is paired with the corresponding lower.
Also see definition of "Pair" in Word Study