3. (Med.)

Defn: Metastasis of an eruption or a tumor from the surface to the interior of the body.

RETROCHOIR
Re"tro*choir, n. Etym: [Pref. retro- + choir.] (Eccl. Arch.)

Defn: Any extension of a church behind the higggggggh altar, as a chapel; also, in an apsidal church, all the space beyond the line of the back or eastern face of the altar.

RETROCOPULANT
Re`tro*cop"u*lant, a. Etym: [See Retrocopulation.]

Defn: Copulating backward, or from behind.

RETROCOPULATION
Re`tro*cop`u*la"tion, n. Etym: [Pref. retro- + copulation.]

Defn: Copulation from behind. Sir T. Browne.

RETRODUCTION Re`tro*duc"tion, n. Etym: [L. retroducere, retroductum, to lead or bring back; retro backward + ducere to lead.]

Defn: A leading or bringing back.