filter
n. countablen. a tool or piece of software that removes things you do not want. You use it to clean water, change how a photo looks, or block certain emails.
n. a device or software program used to separate unwanted elements from a flow of data, light, or liquid. Often functions by allowing only specific components to pass through while blocking others.
You should change the water filter every three months.
She applied a vintage filter to the photo before posting it to her social media profile.
The network administrator updated the spam filter to prevent malicious attachments from reaching the employees' inboxes during the phishing wave.
From Middle English filtre, from Medieval Latin filtrum (compare also Old French feutre (“felt; filter”)), from Frankish filtir, from Proto-West Germanic felt. See felt. Doublet of phin.
Commonly used with the preposition 'for' to describe its purpose, such as a 'filter for' dust or light.