丁内酯

butyrolactone

male adult / the 4th of the 10 Heavenly Stems 天干[tian1 gan1] / fourth (used like "4" or "D") / small cube of meat or vegetable / (literary) to encounter / (archaic) ancient Chinese compass point: 195° / (chemistry) butyl

inside / inner / internal / within / interior

lactone

ester