A monk shoe is a style of shoe

Dress shoe

A dress shoe is a shoe to be worn at smart casual or more formal events. A dress shoe is typically contrasted to an athletic shoe....

 with no lacing, closed by a buckle and strap.

It is moderately formal shoe: less formal than a full Oxford

Oxford shoe

An Oxford is a style of laced shoe characterized by shoelace eyelet tabs that are stitched underneath the vamp, a construction method that is also sometimes referred to as "closed lacing". Oxfords first appeared in Scotland and Ireland, where they are occasionally called Balmorals after the Queen's...

 (American: Balmoral); but more so than an open Derby

Derby shoe

A Derby or Gibson is a style of shoe characterized by shoelace eyelet tabs that are sewn on top of the vamp, a construction method that is also sometimes referred to as "open lacing" where the tongue cut in one piece with the forepart...

 (American: Blücher). In between these, it is one of the main categories of men's shoes.

It often has a cap toe, it is occasionally brogue

Brogues

The Brogue is a style of low-heeled shoe or boot traditionally characterized by multiple-piece, sturdy leather uppers with decorative perforations and serration along the pieces' visible edges...

d, and is popular in suede

Suede

Suede is a type of leather with a napped finish, commonly used for jackets, shoes, shirts, purses, furniture and other items. The term comes from the French "gants de Suède", which literally means "gloves of Sweden"....

.