The top character means “female sheep/ewe.” This marking and the examples below are taken from Before Writing Vol. I (©1992) by Denise Schmandt-Besserat, page 143.
The complex tokens (on the left below) are circa 6,400-5,100 years old (“4400-3100 B.C. [Uruk XVII-IVa]” page 198). The cuneiform on the right is circa 5,000-3,000 years old (3,000-1,000 BC). “Sheep” was represented by a circle (O) with a plus (+) in it. “Ewe” (female sheep) was represented by a circle with a plus and a “V.” A salient body part of the female is the vagina—because it is where the penis enters to inseminate and where the baby emerges when born—which is “V”-shaped, so one logically assumes that this “V” represents female mammal genitalia. This is the first documented time that a “V” signifying for “female” has been used as a recording mechanism by equating one “V” mark inside of the mark for “sheep” which then equals the combined meaning of “one female sheep.” This means that “V” has been equated with the female form in writing for circa 6,400 years.