Praise be to God, and thereafter: What is the meaning of "al-ma'i'at" (مائعات)? And thank you.

Fluids are soluble, non-solid liquids like water, oil, and milk. In the hadith about the mouse that falls into clarified butter, the Prophet, peace and blessings be upon him, said: "If it is fluid, pour it out; and if it is solid, remove what is around it." The meaning of "fluid" here is dissolved and liquid.