At the University of Oxford the three academic terms have special names.
Michaelmas itself is an old British holiday (St Michael's Feast) that falls on September 29th each year. Oxford's Michaelmas term is what in other places might be called the Autumn or Christmas Term. It begins in the first week of October, and lasts until December.
Hilary term is the second academic term of Oxford University's academic year. It runs from January to March. It is the term that begins on the first Sunday after the feast day of St Hilary of Poitiers, 14 January.
Trinity term is the name of the third and final term of Oxford University's academic year. It runs from April to June. Examinations are usually held during seventh week of this term, and are usually followed by a tradition called trashing.