Synonyms bottom
bottom
base ▪ foundation ▪ foot
These are all words for the lowest part of something.
Footnotes are given at the bottom of each page.
I waited for them at the bottom of the hill.
base usually sing. the lowest part of something, especially the part or surface on which it rests or stands: The lamp has a heavy base.
foundation usually pl. a layer of stone, concrete, etc. that forms the solid underground base of a building: to lay the foundations of the new school
foot sing. the lowest part of something: At the foot of the stairs she turned to face him.
bottom or foot?
Foot is used to talk about a limited number of things: it is used most often with tree, hill/mountain, steps/stairs and page. Bottom can be used to talk about a much wider range of things, including those mentioned above for foot. Foot is generally used in more literary contexts.
Patterns
at/near/towards the bottom/base/foot of something
on the bottom/base of something
(a) firm/solid/strong base/foundation(s)