几乎 means 'nearly', 'almost' or 'practically', and is used to emphasize that someone or something 'almost' meets a certain standard or is close to doing something in Chinese grammar.
Structure
subject+几乎+Adjective/verb/[verb phrase]
Examples
Tā jīhū yǒu yì bǎi liànɡ chē.
他几乎有一百辆车。
他几乎有一百辆车。
He has almost one hundred cars.