(photography) Any undesired image appearing at the image plane of an optical system; either a false image of the desired object, or an out-of-focus image of a bright source of light in the field of the optical system.

(computing) A copy of all the contents of a hard drive, used as a backup.

(idiomatic) To arrive casually and unannounced, with little or no warning; also, to visit without an appointment. / (surfing) To paddle into and take off on a wave another surfer is already riding.

Alternative spelling of drop-in.

(figuratively) To follow the same path as someone; to take actions similar to another's.

A branding iron which is not bent into the shape of the mark but rather requires the user to write the desired brand (and thus allows writing any brand).

(soccer, rugby, basketball) A set-piece where the ball is thrown back into play

(banking, finance) Interest, as on a loan or a bank account, that is calculated on the total on the principal plus accumulated unpaid interest.

instead; in place

(idiomatic) Very rarely; very infrequently.