Il dépasse son père d’une tête.
eel day-paas saw pair dewn TETT. Click below to hear this.*
He is taller than his father by a head.
Comparative measurements are sometimes difficult in French. The way you express them often differs wildly from the English. That’s the case here: in the French sentence, there is no taller than at all.
Instead, the typical French approach to this expression is to use a verb. Dépasser means to surpass or to go beyond, which might sound as it is too vague a term. Does it mean he’s smarter than his dad? Does the son have two heads? (My mother and her girlfriends used to joke that they wouldn’t marry someone from MIT, lest their children should have two heads. Blessedly, my father did not attend MIT, and we were born with one head apiece.)
Or maybe it means that the son is faster than his dad. But that only works for racehorses. Bigger feet? More money?
Of course, context is everything. What do we measure in heads in human beings, but height? So the sentence really means He surpasses his father [in height] by a head.
*Some mobile phones, such as Blackberries, won’t display the audio player. If no player appears, here’s an alternative link to the audio file: