pillar

(tree) + (master/mainly)
★☆☆☆☆
9 strokes

Onyomi

CHUU

Mnemonic

The master is standing next to a wooden pillar and CHEWing on it. (FYI there has been inbreeding in the master's family)

Kunyomi

はしら pillar
★☆☆☆☆

Jukugo

電柱(でんちゅう)

telephone pole ☆☆☆☆☆ NEO
(electricity) + (pillar) = 電柱 (telephone pole)

telephone pole. Although, since in Japan all the telephone poles double as light poles (街灯) AND are festooned with every other imaginable cable to boot, I have no idea which word people use!