son, counter for sons
郎 centers on a male child or young man, especially in the context of sons. The counter sense is a natural extension for counting sons.
郎 combines ⻏ (a variant of 邑, meaning a place or settlement) with 良, which likely contributes the sound. Historically it referred to a title for young men or officials, later extending to sons.
The left side 良 suggests something good, and the right side ⻏ looks like a person kneeling. Picture a good young man kneeling respectfully—a son.
For ロウ, imagine a proud father saying 'low' in a deep voice when his son bows low in respect: low -> ロウ.
first son
guy; fellow; chap; buddy
nth son
second son
third son
Momotarō (Japanese folk tale and popular hero)
bridegroom
Kintarō; Golden Boy; folklore boy hero and defeater of demons; usu. depicted with a bob cut, carrying an axe, and wearing a red apron
goddamn idiot; moron; nitwit
Ichitarō
prostitute (esp. Edo period)
amateur; novice; layman
diving beetle
one's family and followers; one's whole clan
Kintarō candy; Kintarō-ame; hard stick-shaped candy made so that the face of folk hero Kintarō appears when it is sliced
jorō spider (Trichonephila clavata)
sweet rice jelly
slow witted fellow; counter-hero; liar
boy; (male) servant
man with an unattractive, unusually shaped face