What is the meaning of Rectus?

Any of several straight muscles in various parts of the body, as of the abdomen, thigh, eye etc.

Ellipsis of rectus abdominis.

Any of a number of muscles controlling the movement of the eyeball.

led straight along, drawn in a straight line, straight, upright.

right, correct, proper, appropriate, befitting.

morally right, correct, lawful, just, virtuous, noble, good, proper, honest.

Source: wiktionary.org