The shared feature of the three words is 预(yù)，which means ‘in advance’. The distinctions of morphemes among the three words decide their semantic differences.
预(yù)订(dìng) means ‘book/reserve’ as 订(dìng) expresses the meaning of ‘book’.
预(yù)定(dìng) means ‘predetermine’ as 定(dìng) expresses the meaning of ‘decide/determine’.
预(yù)约(yuē) means ‘make an appointment’ as 约(yuē) expresses the meaning of ‘invite’.
