* Funnel with filter: This is a descriptive term that accurately describes what it is. Small funnels, sometimes specifically marketed for transferring liquids, often come with a small mesh filter to remove any particulates.
* Filter funnel: Similar to the above, this emphasizes the filtering function.
* Mini strainer: This is a generic term that could apply.
* Fine mesh funnel: Describes the specific type of filter.
In the context of perfume making, you might just see it referred to as a filter or strainer within a set of perfume-making supplies, or as part of a more general description of equipment.
If you're looking to buy one, searching for "small funnel with filter," "laboratory funnel with filter," or "fine mesh funnel" would be good starting points.