eighteenth day of the month

a octadecagon

a special talent or skill that one is good at / an act or expression that one often does

a surname

a pentadecagon

fifteenth day of the month

fifty days / Short for 五十日の祝 (ika no iwai): a Heian-period celebration on the 50th day after a child's birth / Short for 五十日の餅 (ika no mochii): mochi fed to the child during ika no iwai

五日 (itsuka, go-nichi, “fifth (5th) day”) / 十日 (tōka, jū-nichi, “tenth (10th) day”) / 十五日 (jūgo-nichi, “fifteenth (15th) day”) / 二十日 (hatsuka, nijū-nichi, “twentieth (20th) day”)

a person who sells fish; also, such a store

a person who sells fish; also, such a store