l'chaim -- lit.: to life; often said when giving a toast over alcohol
l'chatchilah -- lit.: from the beginning; what the halacha prescribes in the ideal situation, before you've acted (contrast to bidieved)
l'sheim Shamayim -- lit.: for the sake of Heaven; undertaking to perform a good deed without any ulterior motives, others than to do the will of God; sometimes shortened to: lishma
Lag B'Omer -- the 33rd day of the Omer, marking the yahrtzeit (death) of Rabbi Shimon Bar Yochai
lashon hara -- lit.: evil tongue; prohibited gossip, whether true or false
Lecha Dodi -- famous song/poem written by Rabbi Solomon HaLevi Alkabetz (16th century); part of the Shabbat evening service
Levite -- descendant of Levi, the third son of Jacob
Leviticus -- third of the Five Books of Moses
Levush -- Rabbi Mordechai Yaffeh (Prague, Poland 1535-1612), prolific writer on Jewish philosophy and law, who also headed the famous “Council of the Three Lands”
leyn -- to read from the Torah (Yiddish)
losh -- lit.: “kneading”; the forbidden Shabbat activity of mixing two substances to produce something thick and consistent
lulav -- a date palm branch; used on Sukkot as part of the Four Species
