|Truncation or Wildcard
There are three wildcard operators:
An asterisk (*) stands for any number of
characters, including none, and is especially useful when you
want to find all words that share the same root. For example,
pigment* matches pigment, pigments,
pigmentation, etc. Note that you must enter at least three (3) non-wildcard characters. So a search on o* is not allowed; rather you need to enter: oba*.
An asterisk can also be used within a word, but the other wildcards are more precise for this kind of use.
A question mark (?) stands for exactly one
character and is especially useful when you're uncertain of a
spelling. For example, a search like relev?nce means
you can match the word relevance even if, like many of us, you
can't remember whether it's spelled with ance or
A question mark is also useful for finding certain words with
variant spellings. For example, defen?e finds both
defense (American) and defence (British and Canadian).
Multiple question marks in a row stand for the same number of
characters as there are question marks. For example,
psych????y matches either psychology or
psychiatry but not psychotherapy.
An exclamation point (!) stands for one or no
characters and is especially useful when you want to match the
singular and plural of a word but not other forms. For example,
product! matches product and products
but not productive or productivity. The exclamation point
can also be used inside a word to match certain variant spellings. For
example, colo!r matches both color (American)
and colour (British).
If you see a message about a search being invalid, try adding more letters before the wildcard character.