Posted on 07/06/2012 by __socrates

Wikis > Dictionary of Islam > Sajdatu's-Sahw

SAJDATU ‘S-SAHW صجدة السهو
“The prostrations of forgetfulness.” Two prostrations made on account of forgetfulness or inattention in prayer. Muhammad said, “When any of you stand up for prayer, and the devil comes to you and casts doubt and perplexity into your mind, so that you do not know bow many rak’ahs you have recited, then prostrate yourself twice.

Based on Hughes, Dictionary of Islam