Substantiate is a related term of second.
In lang=en terms the difference between substantiate and second
is that
substantiate is to give material form or substance to something; to embody; to record in documents while
second is to agree as a second person to (a proposal), usually to reach a necessary quorum of two.
As verbs the difference between substantiate and second
is that
substantiate is to verify something by supplying evidence; to authenticate or corroborate while
second is (uk) to transfer temporarily to alternative employment.
As an adjective second is
number-two; following after the first one with nothing between them the ordinal number corresponding to the cardinal number two.
As an adverb second is
(with superlative) at the second rank.
As a noun second is
one that is number two in a series or
second can be the si unit of time, defined as the duration of 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of caesium-133 in a ground state at a temperature of absolute zero and at rest; one-sixtieth of a minute or
second can be one who supports another in a contest or combat, such as a dueller's assistant.