a tenth of an ephah: a fixed dry measure of flour, roughly two quarts, used in the grain offerings
This word names a set amount of flour, not a vague fraction. It is one tenth of an ephah, the standard large dry measure, which works out to about two quarts or two liters. The same amount was elsewhere called an omer, the measure used for gathering the manna.
Almost every time it appears, it is a recipe line in the sacrificial laws: so many tenths of fine flour, mixed with oil, to accompany a burnt offering or other sacrifice. The quantity scales with the animal being offered, so the texts speak of one tenth for a lamb, two tenths for a ram, and three tenths for a bull.
Because it is a unit of measure rather than a description, it carries no shades of meaning to sort out. The interest of the word is practical: it tells the reader exactly how much flour a given offering required.