what can be the best definition of SEO?

[dzeff]

I have almost come across those 3 letters every time I do some research online related to internet marketing.

[M]

Stands for Search Engine Optimisation. It's describes the method in which a search engine measures or grades the popularity of a website. Example: A website will use search engine optimisation in order to be represented as the first item returned in a search result.

[KIRUI GEOFFREY]

In my own definition, I'll take it to mean adding words, for example in meta description in your website or or simply placing several keywords that can be easily picked by search engines such as google.

[Hassan Ahmed]

Well SEO Stands for Search Engine Optimization, You can understand it easily. There are two term present in it full form that are Search Engine (Google, Yahoo, Bing) and Optimization. It's means that how can you optimize your site or blog for search engines. SEO is define as A process in which A user optimizes it's site or blog to get top positions in SERP (search Engine Ranking Pages).
Some basic Factors of SEO:
1 - On Page Optimization
2 - Off Page Optimization
3 - Meta Description
4 - Keyword Targeting
5 - Image Optimization
6 - Nofollow and Dofollow Links
some more...

[Nuha]

The task to make your site visibility on the Search Engine is simply SEO.

[Mind]

SEO is a collective name for multiple processes that are implemented to make sure that for the keywords related to your business, your website in ranked higher in search engines so that your website gets more visitors or potential customers to your business.

[Dan L]

Search Engin Optimization, setting your page up to be optimize for search engins.