槓子 is read as かんつ (kantsu) and means kong.
かんつ
kantsu
さんかんつ
three kongs
すーかんつ
winning hand consisting of four kongs and a pair
さいし
wife
おやこ
parent and child
ふたご
twins
でし
pupil
とうがらし
shichimi pepper
ぎょーざ
gyoza
ぼし
mother and child
なす
eggplant (Solanum melongena)
ちょうし
trend
ようす
sign