Some of the tech's and buildable items have either an all-caps (DEF) or (ITER) in the description.  What's the meaning?

DEF means that those buildings increase manpower deployment limit that determines your defences upon invasion. Don't know about ITER though, what are those techs/improvements?

looks like ITER stands for Intergalactic Technology Center

Thanks everyone for the detailed explanations and screenshots!  That makes things very clear now.