沿う[sou] to run along
沿って[sotte] along
沿海[enkai] coast
沿革[enkaku] history
沿岸[engan] coast

沿線[ensen] along railway line
沿道[endou] route
沿路[enro] route
海沿い[umizoi] coastlands
河沿い[kawazoi] along the river

介添え[kaizoe] helper
寄添う[yorisou] to get close
後添い[nochizoi] one's second wife
食品添加物[shokuhintenkabutsu] food additive
申し添える[moushisoeru] to add to what has been said

添う[sou] to meet (one's expectations, etc.)
添加[tenka] addition
添加剤[tenkazai] addition agent
添加物[tenkabutsu] addition
添削[tensaku] correction