Oak, subs. (University).—An outer door. To sport one’s oak = to be “not at home,” indicated by closing the outer door.
1785. Grose, Vulg. Tongue, s.v.
1840. The Collegian’s Guide, 119. In college each set of rooms is provided with an OAK or outer door, with a spring lock, of which the master has one key, and the servant another.
1853. Bradley (“Cuthbert Bede”), Verdant Green, iv. This is the HOAK, this ’ere outer door is, sir, which the gentlemen sports, that is to say, shuts, sir, when they’re a-readin’. Ibid., viii. Mr. Verdant Green had, for the first time, SPORTED HIS OAK.
1861. Hughes, Tom Brown at Oxford, vii. One evening he found himself as usual at Hardy’s door about eight o’clock. The OAK was open, but he got no answer when he knocked at the inner door.
1891. Harry Fludyer at Cambridge, 55. He tried to keep them out, but they broke in his OAK, stripped him, tied him up in his table-cloth, and left him on the grass plot where the porter found him.
Ob, subs. (Winchester).—A contraction of obit.
Obeum (The), subs. (Cambridge).—A water-closet building at King’s College. [Attributed by the undergraduates to the energy of O[scar] B[rowning].]
Off-bat, subs. (Winchester: obsolete).—“Point”: at cricket.