煙海

the vast ocean

surname Hai

ocean / sea / CL:個|个[ge4],片[pian4] / great number of people or things / (dialect) numerous

cigarette or pipe tobacco / CL:根[gen1] / smoke / mist / vapour / CL:縷|缕[lü3] / tobacco plant / (of the eyes) to be irritated by smoke

vast as the open sea (idiom); fig. extensive (library)