What's the difference between i.e. and e.g.?
Old English forð "forward, onward, further, continually," perfective of fore, from Proto-Germanic *furtha- (cf. Old Frisian, Old Saxon forth "forward, onward," Old Norse forð, Dutch voort, German fort), from PIE *prto-, from *pr-, from root *per- (1) "forward, through" (see per).