(typography) the ban on separating multiple successive instances of certain leading punctuation marks, such as multiple successive em dashes, wavy dashes, two-dot leaders, ellipses, etc., during line breaking

(neuroscience) chemotransmitter

to separate / to segregate

separation / segregation / selectivity or sensitivity in a radio or similar device for certain frequencies

material, substance

chemistry (branch of natural science)

prohibition

to ban; to prohibit

chemistry (branch of natural science)

separation of politics and religion