If you have allergies, pregnancy can make your symptoms worse. But you're right to worry about taking allergy medicine during pregnancy. Pregnant women shouldn't take some allergy drugs. Certain antihistamines, however, are safe.
free radical. (chemistry). An atom or a diatomic or polyatomic molecule which possesses one unpaired electron. Also known as a radical.ree radical. in chemistry, a molecule or atom that contains an unpaired electron but is neither positively nor negatively charged. Free radicals are usually highly reactive and unstable.
noun. In the 1960s hippies, were considered radicals. In the 1960s hippies, were considered radicals. The definition of radical is something that is at the root of something, or something that changes, addresses or affects the major essence of something. 1  An example of radical is a basic solution to a complex problem. 2  An example of radical is the change that allowed women to vote.