n-gram

Introduction:

Wikipedia defines  An n-gram as:  a subsequence of n items from a given sequence. The items in question can be phonemes, syllables, letters, words or base pairs according to the application.

An n-gram of size 1 is referred to as a "unigram"; size 2 is a "bigram" (or, less commonly, a "digram"); size 3 is a "trigram"; and size 4 or more is simply called an "n-gram".

Usages

n-grams are used in various areas of statistical natural language processing and genetic sequence analysis.

Examples:

Examples of word level 3-grams and 4-grams (and counts of the number of times they appeared) from the Google n-gram corpus.

• ceramics collectables collectibles (55)
• ceramics collectables fine (130)
• ceramics collected by (52)
• ceramics collectible pottery (50)
• ceramics collectibles cooking (45)

4-grams

• serve as the incoming (92)
• serve as the incubator (99)
• serve as the independent (794)
• serve as the index (223)
• serve as the indication (72)
• serve as the indicator (120)

References:
1. Wikipedia: N-Gram