Broad match means the keywords you have set in your campaign can be fetched other than the exact match. For eg: if you have included rings for women under broad match, your ad can also be visible when someone searches for gold rings for women or diamond rings for women and so on.
Broad match is the default match type and the one that reaches the widest audience. When using broad match, your ad is eligible to appear whenever a user’s search query includes any word in your key phrase, in any order.
Basically, broad match is a keyword match type that search engines use to determine which search terms your ads are eligible to match against. It's called "broad" because it allows your ad to match the widest range of possible keyword searches that are still somewhat related to your keyword.
Google defines broad match as:
Broad Match - This is the default option. If your ad group contained the keyword tennis shoes, your ad would be eligible to appear when a user's search query contained tennis and shoes, in any order, and possibly along with other terms. Your ads could also show for singular/plural forms, synonyms, and other relevant variations. For example, your ad might show on tennis shoe or tennis sneakers.
The expansive match gives a catchphrase a chance to trigger your promotion to indicate at whatever point somebody looks for that expression, comparable expressions, particular or plural structures, incorrect spellings, equivalent words, stemming, (for example, floor and ground surface), related pursuits, and other significant varieties.
Broad match keywords allows the advertising platform to display your ad to individuals on a broad basis. What this means is that your keyword(s) will be matched to search terms that not only match your keyword but are also related to your keyword.
Broad match is a type of match which you set to your keyword. When your customer has a desire but he is not aware about that so much . Like someone want to buy a mobile but he is not sure what kind of mobile phone he will buy .so broadly search for keyword which match with your keyword and ad appear.