1) BDSM terminology 2) Sexual pleasure 
Algolagnia (ə; from άλγος, algos, `pain`, and λαγνεία, lagnia, `lust`) is a sexual tendency which is defined by deriving sexual pleasure and stimulation from physical pain, often involving an erogenous zone. Studies conducted indicate differences in how the brains of those with algolagnia interpret nerve input. ==History of resear...
sexual pleasure derived from inflicting pain
Form of sexual perversion in which the infliction or the experiencing of pain increases the pleasure of the sexual act or causes sexual pleasure independent of the act; includes both sadism (active algolagnia) and masochism (passive algolagnia). ... Synonym: algophilia. ... Origin: algo-+ G. Lagneia, lust ... (05 Mar 2000) ... 
Type: Term Pronunciation: al-gō-lag′nē-ă Definitions: 1. Obsolete term for algophilia.
Algolagnia (algophilia) is a psychological term for the love of pain in sex.
[n] - sexual pleasure derived from inflicting or experiencing pain
algolagnia A form of sexual perversion in which the infliction or the experiencing of pain increases the pleasure of the sexual act or causes sexual pleasure independent of the act; includes both sadism (active algolagnia) and masochism (passive algolagnia); also: algophilia.
algophilia noun sexual pleasure derived from inflicting or experiencing pain
sexual pleasure derived from enduring or inflicting pain, as in masochism or sadism.