Terry Boot is a Ravenclaw boy in Harry’s year at Hogwarts. Terry checked out Quidditch Through the Ages on 21 August (QA). He joined the DA October 1995, apparently having heard about it as a friend of Michael Corner (OP16). He was one of the DA members who helped Harry cope with Malfoy in the ambush on the Hogwarts Express (OP38). Terry was an active member of the DA resisting Snape and the Carrows in his seventh year; he was beaten up by the Carrows for yelling in the Great Hall about Harry’s break-in at Gringotts (DH29). Terry fought in the Battle of Hogwarts (DH31).
In 2001 Rowling flashed a notebook during a BBC interview that showed her notes on the students in Harry Potter's year and Terry is noted as being a male Muggleborn in Ravenclaw House. Boot's ancestry cannot be considered canon, however, because the notes conflict in too many places with the stories as they were actually published. In fact, Terry must be either a half-blood or a pure-blood, because he attended Hogwarts when it was illegal for Muggle-borns to do so (DH29).
Terry excels at Potions, among other things, because he earned an O on his Potions O.W.L., thereby enabling him to take Potions at the N.E.W.T. level (HBP9).
He is also shown to be fairly knowledgeable about Charms, demonstrating prior knowledge of the Protean Charm when Hermione hands out the DA Galleons (OP18).
Other canon notes and references
Sometime during the 1995-1995 school year Terry visited Dumbledore's office, where a portrait told Terry about Harry Potter killing the basilisk with the Sword of Gryffindor - which was also in the Headmaster's office. (OP16).