Globbing is the term for pattern matching that shells use to expand wildcards like * or ?. In zsh, globbing patterns can be followed by a list of qualifiers inside of parenthesis, which restrict the filenames that match the glob.

For example, here are a few globs with simple modifiers:

# . modifier means all "plain files"
% ls *(.) 
foo.txt  bar.jpg

#  * modifier means all "executable plain files"
% ls *(*)        

Normally, the * wildcard would match and expand to all files in the directory (except hidden dot-files). However, with a modifier specified in parens after the glob, you can qualify or restrict your glob.

Besides filtering, you can also specify sorting qualifiers:

oc — sort by criteria c ascending.
Oc — sort by criteria c descending.

Where criteria c can be:

n   name  (default)
L   size (length) of file
a   access time
m   modification time
c   creation time

Here is the magic, qualifiers can actually be indexed with square braces of the form [beg[,end]]. For example, you can get the most recently modified file:

# glob for the newest file by modification
% ls -lha *(om[1])

# glob for the oldest file by modification
% ls -lha *(Om[1])