The difference between Pigeonhole and Shelve

When used as nouns, pigeonhole means a nook in a desk for holding papers, whereas shelve means a rocky ledge or shelf.

When used as verbs, pigeonhole means to categorize, whereas shelve means to place on a shelf.

check bellow for the other definitions of Pigeonhole and Shelve

Pigeonhole as a noun:

A nook in a desk for holding papers.
Pigeonhole as a noun:

One of an array of compartments for sorting post, messages, etc. at an office, or college (for example).

Examples:

"Fred was disappointed at the lack of post in his pigeonhole."
Pigeonhole as a noun:

A hole or roosting place for pigeons.
Pigeonhole as a noun (historical):

An Ancient Roman system of storage, used in libraries for keeping scrolls.

Pigeonhole as a verb:

To categorize; especially to limit or be limited to a particular category, role, etc.

Examples:

"Fred was tired of being pigeonholed as a computer geek."
Pigeonhole as a verb:

To put aside, to not act on (proposals, suggestions, advice).

Shelve as a verb (transitive):

to place on a shelf

Examples:

"The library needs volunteers to help shelve books."
Shelve as a verb (transitive):

to set aside, quit, or halt

Examples:

"They shelved the entire project when they heard how much it would cost."
Shelve as a verb:

To furnish with shelves.

Examples:

"to shelve a closet or a library"
Shelve as a verb (slang):

To take (drugs) by anal or vaginal insertion.
Shelve as a verb (Wales, slang):

To have sex with.
Shelve as a verb (intransitive):

To slope; to incline.