Keyword
A keyword is the expression targeted in search engines: the query a user types. Each keyword is characterized by its search volume, competitive difficulty, and the intent it reveals.
In practice
Keyword selection determines everything downstream: a hundred well-chosen expressions — achievable, aligned with the offering, distributed across intents — outperform a thousand pulled in bulk. Each maps to a unique target page to prevent the site from cannibalizing itself. Tracking happens position by position, week after week.