Tree - the (hopefully still) living thing stuck in a bonsai pot.
Pot - the container the tree is stuck in.
Soil - dirt.
Roots - parts of the tree under the soil surface.
Surface roots - parts of the roots above the soil surface.
Base - the surface roots and the lower flare of the trunk (see below).
Trunk - the part of the tree that connects the roots and surface roots to the branches.
Branches - the thinner woody parts of the tree that come off the trunk.
Foliage - the tree's leaves or needles: that is, the green (sometimes other colors) most distal parts of the tree that fan out from the branches.
Flowers - the sexual parts. Often brightly colored.
Fruits - the seeds, covered with a thin or thick skin and pulp, used by the tree to propagate.
Buds - latent or growing clusters of tissue from which new growth emerges.
Heartwood - the inner, dense, dry, dead, structural wood.
Sapwood - the outer, softer, moist, quasi-living wood.
Cambium - the thin, green, living layer between the sapwood and the bark.
Bark - the thick, dead, outer covering of the roots, trunk and branches.
Deadwood features - exposed areas of sapwood and heartwood.
Watering - what we do to keep the tree alive.
Feeding - what we do to keep the tree healthy.
Styling - what we do to make the tree pretty.
Enjoying - what we do for ourselves.