- Pre-eminent
- Standing out above all the others. Snowball and Napoleon are pre-eminent among the pigs, which marks them as the leaders from the start.
- Porker
- A pig, especially a castrated male, fattened to be killed for meat. Every male pig on the farm except the two young boars, Snowball and Napoleon, is a porker, Squealer among them.
- Vivacious
- Lively and full of energy. It is the word that first separates Snowball from the quieter, more forceful Napoleon.
- Animalism
- The complete system of thought the pigs build from Old Major's teaching. In the allegory it stands for communism as a set of ideals.
- Apathy
- Lack of interest or concern. It is what the pigs meet at the first secret meetings, when some animals ask why they should care about a future they will not live to see.
- Expounded
- Explained in detail. The pigs expound the principles of Animalism to the others, which puts them in the position of teachers from the beginning.
- Disciples
- Devoted followers of a teacher, a word with religious overtones. Boxer and Clover are the pigs' most faithful disciples.
- Tale-bearer
- Someone who spreads gossip or tells tales about others, getting them into trouble. Moses is one, which is part of why the animals hate him.
- Blinkers
- Flaps on a horse's bridle that stop it seeing behind or to the side, so it looks only ahead, where it is driven. The animals burn them with the reins, halters and nosebags.
- Knoll
- A small, rounded hill. From the knoll the animals first look out over the farm as its owners.
- Unanimous resolution
- A decision agreed by everyone at a meeting. The animals pass one to keep the farmhouse as a museum, but it is not among the Commandments, and in Chapter 6 Squealer persuades them it was never passed.
- Stove in
- Broken inwards by a blow. The barrel of beer in the scullery is stove in by a kick from Boxer, the animals' rejection of the drink that helped to ruin Jones.