Semper Aequitas - Equality always (Philosophical term)
Semper Alere Flammam - Always feeding the flame (Motto of prep school #8 of the University of Nuevo Leon, Mexico)
Semper Ascendens - Always Ascending (Motto of State of Nuevo Leon, Mexico)
Semper deinceps - Always forward (Motto of GA-935 JROTC raider team - Thank you: Kendall)
Semper Fidelis - Always Faithful (Marine Corp Motto)
Semper gumby - Always flexible (Motto of the US Air Force - This sentence is a hack, it is evident that "gumby" is not Latin)
Semper idem - Always the same (Cicero)
Semper novarum rerum cupidus - Always eager to learn new things
Semper Paratus - Always Ready (Motto of the United States Coast Guard - Thank you: E. Oleson)
Semper primus - Always first (Motto of the US Navy)
Semper ubi sub ubi - Always wear underwear (Thank you: Hunter Martin )
Senatores non sciebant quare imperator id iussisset - The Senators did not know why the emperor had ordered this
Senatus Consultum - Senate's decree
Senatus PopulusQue Romanus - The Senate and People of Rome (Often abbreviated as SPQR)
Senatus populusque romanus intelligit - The Senate and the Roman people understand (During the Roman Empire, this phrase was used with proposals to be presented to the Senate)
Senectus ipsa est morbus - Old age itself is a disease
Senior - Older
Sensim sine sensu aetas senescit - Insensibly, without feeling, life is aging. (Cicero - De Senectute)
Sensu latissimo - In the broadest sense
Sensu strictissimo - In the strictest sense
Sententia debet esse conformis libello - The sentence must be consistent with libel (Legal term)
Sermo cotidianus - Normal street language (Lucilius - Book of Satires)
Sermo rusticus - The language used in the country side
