ADJ

false
a case with a false bottom

VERB + BOTTOM

arrive at, fall to, get to, reach, sink to
He reached the bottom of the steps in no time. The boat sank to the bottom of the sea
touch
She could only just touch the bottom (= of a swimming pool, etc.)

BOTTOM + NOUN

end, half

PREP

along the ~
We rode along the bottom of the valley
at the ~
at the bottom of the hill
from the ~
strange sounds from the bottom of the well
in the ~
in the bottom of my bag
on the ~
on the bottom of the box
near/towards the ~
near the bottom of the page

VERB + BOTTOM

start at, work up from
He started at the bottom and worked his way up through the company

PREP

at the ~, near/towards the ~
He's near the bottom of the class

ADJ

bare

VERB + BOTTOM

smack

VERB + BOTTOM

be at, lie at
I'd love to know what lies at the bottom of all this
get to
The only way to get to the bottom of it is to confront the chairman