Ranks

Warriors - the ones who protect the clan

Apprentices - Those who are in training to become warriors. Every apprentice either becomes a medicine cat or a warrior. Medicine cats can also take

Deputy - Second-in-command to the leader

Queens - The she-cats who give birth to the kits.

Medicine Cat - Kinda like a healer

Kit - a baby cat, a kitten

Elders - the oldest cats in the clan.

Kittypet - a domesticated cat.

Loner - a cat without a defined territory

Rogue - A usually hostile cat who does not have a permanent home, roams around, and does not care about crossing Clan boundaries. [Directly from the Wiki, word-for-word.]

Other words

Freshkill - freshly killed prey

Patrol - a group of cats either hunting or making sure that the clan is safe and there are no intruders.

Sharing tongues - a time when cats gossip with and groom one another.

Silverpelt- a swathe of stars in the sky where it is believed that the deceased now reside. Kind of like cat heaven.

StarClan - located within Silverpelt, it's the clan of the cats who have passed on.

Twolegs - humans
Twoleg kit - babies/toddlers

Seasons/Time

Newleaf - spring

Greenleaf - Summertime

Leaf-fall - Fall/autum

Leaf-bare - winter

Moon - about a month

Moonhigh - the point at which the moon is highest in the sky.

Sunhigh - Around noon, when the sun has reached its highest point.

That's all I can think of for now XD Credit to all the terms goes to Kate Cary, Cherith Baldry, Tui Sutherland, Gillian Philip, Inbali Iserles and Victoria Holmes (aka Erin Hunter)