ad hoc http://en.wikipedia.org/wiki/Ad_hoc
i.e. [1]http://en.wikipedia.org/wiki/List_of_Latin_phrases:_I#id_est
e.g.http://en.wikipedia.org/wiki/Exempli_gratia#exempli_gratia
a priori http://en.wikipedia.org/wiki/A_priori_and_a_posteriori
Q.E.D http://en.wikipedia.org/wiki/Q.E.D.