The asterisk (*) stand for any sequence of characters, including an absence of characters. Examples:

aal* finds all words that begin with "aal": aal, aaleem, aaloc, aalxo, aalk, etc.

*aal finds all words ending with "aal": aal, aejaal, agzonaal, bilkaal, etc., a hundred shrub and tree names.

Some more useful examples: *on and *opa

*viel* finds all words that contain "viel", all kinds of derivates of "viel" such as milvielaf, toleaviel, etc. as well as derivates of "viele".

The question mark (?) stand for any single character.

s? finds all two-character words that begin with "s": sa, se, sé, sí, sú, su.

Also try ?iel and la?í.