Code:

grep -F -e 'out' -e 'outside'  somefile

Fixed strings (-F) eliminates problems with characters like * or [ that can be taken as part of a regular expression. -F turns off regex interpretations and searches so you find exactly what you type inside the single quotes.

PS - the pipe character performs alternation (sort of like an or) and only works in regex mode. So

Code:

grep '\b(out|outside)\b' somefile

would be how to correctly use alternation for those two whole words.