Google Adwords Broad Match Modifier
Adwords has recently expanded the range of keyword matching options available to include a new "broad match modifier" category.
This enables you to target a broader range of terms than the phrase option but be more specific than standard broad matching.
To use the modifier you place a plus "+" symbol in front of one or more words that you want to appear in the search phrase.
Adwords will continue to match close variants such as plurals or misspellings but the word must appear in the user's search.
For further information please refer to: