Avos: tractate of Mishnayos containing ethical
matters
baal(ay) t'shuva: returnee(s) to Jewish observance
bais din: religious court
Bais Hamikdosh: Temple (in Jerusalem)
Chazal: the Sages (of blessed memory)
chillul (Shabbos): desecration of the Sabbath
chinuch: education (Jewish)
Chumash: Five Books of Moses
chumrah: halachic stringency
emunah: faith
frum: (Yiddish) observant (also: extra observant)
Gemara: sixty volume work explaining the Mishnah
(also, Talmud)
gematrios (p): numerical equivalents to Hebrew
letters; a method of exposition
godol (gedolei) hador: greatest Torah scholar(s)
of a generation
haggada: the story of the exodus from Egypt
told over on Pesach
hakhel: once-in-seven-years' gathering of
Jews in the Temple
Halacha: body of Jewish law
kedushah: holiness
kivud av vo'aim: (mitzvah of) honoring one's
parents
kohen: one of priestly lineage
loshon harah: slander
lulav: one of four species used on Succos
mazel: those facets of a person's life (character or situation) which are, to a degree, preordained
midos: character traits
mesorah: unbroken transmission of the Torah
(esp. Oral Torah)
Mishnah: the halachos in their original written form
mitzvah: commandment (divine)
mohel(im): expert(s) in circumcision
poskim: halachic codifiers
pshat: simple meaning of a text
rebbe: teacher
rechilus: talebearing (causing hatred between
people)
Shabbos: the Sabbath
Shas: the whole Gemara
shlep: (Yiddish) to drag (among other, more colorful, meanings)
shochet(im): ritual animal slaughterer(s)
shul: (Yiddish) synagogue
Shulchan Aruch: code of Halachah
talmid chochom: Torah scholar
talmud Torah: Torah studyTanach: twenty-four
books of the written Torah
tefilah: prayer
Torah: usually used to denote the whole body
of divinely inspired works. More specifically, Chumash
Tosafos: commentary on the Gemara by a collaboration
of Medeival scholars
tzitzis: four cornered garment worn with strings
tied at each corner
Yeshaya: the prophet Isaiah
yeshivah: centre for Torah study
yeitzer harah: evil inclination
yeitzer hatov: good inclination
Yom Tov: holy day; festival