1
general::
verb ADV. easily, neatly, simply | together The panels slot together to make a compost bin. PREP. between, in, into He slotted the magazines neatly into the rack. PHRASES slot (sth) into place All the pieces of the puzzle now slotted into place.
Oxford Collocations Dictionary
2
general::
slot sb/sth in
to find time to see someone or do something between various other arrangements that have already been made
• Doctor Meredith is busy this morning, but she might be able to slot you in around one o'clock.
Cambridge-Phrasal Verbs