柚 has two readings. As
柚木 (teak) it is yòu, fourth tone. As the fruit pomelo (
柚子 yòuzi) it is also yòu. But be careful: some dictionaries confusingly gloss
柚木 as 'pomelo tree'; in modern usage
柚木 specifically means teak (the South and Southeast Asian hardwood), not the citrus tree.
