This app searches a list of 164,000 words for matches to a given Pattern.
The are 2- through 14-letter words. See options.

A Pattern consists of letters and/or wildcards (?, #, and *):
? matches any letter in a word
# matches any letter occurring ONCE
* matches 0 or more letters

For example, if Pattern contains the first string below, then after the Search button is tapped, you will see, among other matches:

?ought matches Bought, Fought, Nought, Sought.
??ought matches BRought, DRought, THought, WRought.
##ought matches BRought, DRought, WRought, not THought (T occurs twice).

So # is like ? but more restrictive.

*ought matches BESought, BETHought, Bought, DREADNought ... ought.
So * is like a varying number (including 0) of ? wildcards.

(NOTE: Press the device's BACK button for a new search.)
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Wildcards may be used multiple times:

?ough* matches Bough, BoughS, BoughT, CoughED, RoughHOUSED ...
#ough* matches all the above except RoughHoused (H occurs twice)
#ough#* matches all the above except Bough (the second # requires a letter after h) and RoughHOUSED.
*j*j* matches 33 words, including HAjj, HAjjIS, jEjUNE, jUjISTU
########### matches all 11-letter words in the "dictionary" in which no letter repeats: 348 words.
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??????????? matches all 11-letter words: 15,500 words, but
using option EXCLUDE E returns only 3478, while
adding option that Z be REQUIRED returns only 133--
i.e., there are 133 11-letter words WITH Z but NO E.
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Optional input:
- Legal: Letters on which to base search (default: A-Z)
- Exclude: Letter(s) that may not appear in matches
- Required: Letter(s) that must appear in matches
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Preference options:
- number of matches returned (default 100)
- lengths of shortest and longest words to return (NOTE: longest defaults to 11)
- Legal letters treated as Scrabble tiles

If matches outside the set ranges exist, a notification is issued.
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If NO wildcard appears in a pattern, the word is simply searched for regardless of selected options.

If ONLY wildcards appear in a pattern, the search can take awhile since 164,000 words have to be searched.

Using # precludes having ANY letter appear more than once in the word, so # may not be used with ?.
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Pressing and holding the Pattern field will show how many characters have been entered into it.
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It takes a minute to create a database of all the words. This is a one-time task.
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Example output follows (Legal in all cases is A-Z).

(restricted single-letter match) returns 11 matches:
xylan
xylans
xylem
xylems
xylocarp
xylocarps
xylograph
xylographic
xylographs
xyloid
xylose

(The pattern (unrestricted) returns 32 matches, adding xylene, xylidin, xylyl, etc.)

(unrestricted) returns 7 matches:
xylans
xylems
xylene
xyloid
xylols
xylose
xylyls

(restricted) returns only 4 matches:
xylans
xylems
xyloid
xylose

13 words start with x and end with e, allowing repeats.

x*e returns all 13 matches.
x*?e does, too (all returned words are longer than 3 letters).

x???*???e returns 11 (2 words have fewer than 8 letters).
x???*???e = x*??????e = x??????*e = x?*?*?*?*?*?*e
x*#e returns only xylose (other 12 have repeated letters).
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The word list was downloaded from ENABLE.TXT and OSPD.TXT from www.puzzlers.org, which says, "The Enhanced North American Benchmark LExicon (ENABLE) is the most carefully researched, and therefore the most authoritative[,] dictionary list and reference available... The dictionary list is ... non-proprietary, free, and freely available for any legal use... as ... a benchmark...."

OSPD contains 80,000 words of 8 letters or fewer. ENABLE contains 170,000+ words (of length 2 through 28). The 9- through 14-letter words from ENABLE were merged to form a 164,000-word list of 2- through 14-letter words.

The word lists at www.seattlescrabble.org/expurg.php were used to delete words deemed offensive.