See Methylal.

Belonging to the form, shape, frame, external appearance,
or organization of a thing.

Belonging to the constitution of a thing, as distinguished
from the matter composing it; having the power of making a thing what
it is; constituent; essential; pertaining to or depending on the forms,
so called, of the human intellect.

Done in due form, or with solemnity; according to regular
method; not incidental, sudden or irregular; express; as, he gave his
formal consent.

Devoted to, or done in accordance with, forms or rules;
punctilious; regular; orderly; methodical; of a prescribed form; exact;
prim; stiff; ceremonious; as, a man formal in his dress, his gait, his
conversation.

Having the form or appearance without the substance or
essence; external; as, formal duty; formal worship; formal courtesy,
etc.

Dependent in form; conventional.

Sound; normal.