grep -o(--only-matching)

 -o, --only-matching
              Show only the part of a matching line that matches PATTERN.

grep -w(--word-regexp)

-w, --word-regexp

Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a non-word constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word-constituent characters are letters, digits, and the underscore.