A straight line in space with which a definite linear
magnitude termed the pitch is associated (cf. 5th Pitch, 10 (b)). It is
used to express the displacement of a rigid body, which may always be
made to consist of a rotation about an axis combined with a translation
parallel to that axis.

An amphipod crustacean; as, the skeleton screw (Caprella).
See Sand screw, under Sand.

An extortioner; a sharp bargainer; a skinflint; a niggard.

An unsound or worn-out horse, useful as a hack, and commonly
of good appearance.

An instructor who examines with great or unnecessary
severity; also, a searching or strict examination of a student by an
instructor.

A steam vesel propelled by a screw instead of wheels; a
screw steamer; a propeller.

Specifically, a kind of nail with a spiral thread and a head
with a nick to receive the end of the screw-driver. Screws are much
used to hold together pieces of wood or to fasten something; – called
also wood screws, and screw nails. See also Screw bolt, below.

A cylinder, or a cylindrical perforation, having a
continuous rib, called the thread, winding round it spirally at a
constant inclination, so as to leave a continuous spiral groove between
one turn and the next, – used chiefly for producing, when revolved,
motion or pressure in the direction of its axis, by the sliding of the
threads of the cylinder in the grooves between the threads of the
perforation adapted to it, the former being distinguished as the
external, or male screw, or, more usually the screw; the latter as the
internal, or female screw, or, more usually, the nut.

Anything shaped or acting like a screw; esp., a form of
wheel for propelling steam vessels. It is placed at the stern, and
furnished with blades having helicoidal surfaces to act against the
water in the manner of a screw. See Screw propeller, below.

A small packet of tobacco.