Object vs NMesh

hello

being new to blender and python

could someone explain the exact difference between Object and NMesh ?
and what their linking in code exactly does:
ob.link( nmesh )

any resources that explain all that well ?

thank
s

and also the difference between Mesh and NMesh please ?

Object is a storage container for the NMesh

NMesh contains the actual faces, edges, and verts

Mesh is a ‘thin wrapper’ over the Blender mesh data, whereas NMesh is a ‘fat wrapper’ - thin wrapper is faster, but is sometimes less easy to work with or manipulate than NMesh is.

LetterRip