(theater, film) An actor who has a minor role in a production. / (figuratively) An insignificant or unimportant person (in a particular situation).

plural of plasma rifle

(Britain) Practicum (college course).

(geology) The planar surface between adjacent strata

(idiomatic) To habitually demonstrate interpersonal skills by engaging agreeably in social or work activities.

(literally) Describing actions or activities that the speaker considers inappropriate, misdirected, or unlikely to yield good results.

(idiomatic) to act cool

A protocol, agreed between mother, midwives and doctors, listing options such as birth companion, position at birth, pain relief etc.

(anatomy) Any vertical plane that divides the body into anterior and posterior (belly and back) sections.

(anatomy) Any plane that divides the body into superior and inferior parts, roughly perpendicular to spine.