前沿

qian2 yan2

front-line; forward position; outpost; extending ahead; frontier (of science, technology etc)

沿革

yan2 ge2

evolution of sth over time; course of development; history

沿用

yan2 yong4

to continue to use (old methods); to apply as before; according to usage

边沿

bian1 yan2

edge; fringe

沿岸

yan2 an4

coastal area; littoral or riparian