Alternative form of 跡

(spatially) the back, the rear, behind / (temporally) later, afterwards, some time after the present / the rest

once upon time / period of time

atto-

a surname

then / soon afterward; after that; thereafter

(後 "spatially behind") to depart from; to leave / (後 "temporally later") to put off something, to be dealt with later

(archaic) regrettable; regretful / (archaic) unfortunate / (archaic) tragic / (archaic) precious; valuable

one day

experimental results