During his broadcast Thursday, Limbaugh said defenders of traditional marriage have lost because "we lost the language on this."
Limbaugh took issue with the idea that the word "marriage" already applied to same-sex couples. He noted that explanatory words such as "hetero" or "opposite-sex" are added to denote a union between a man and a woman.
"I don't care what the Supreme Court does, this is now inevitable," Limbaugh said, "and it's inevitable because we lost the language on this."
This week the justices heard two cases involving same-sex marriage. One seeks the repeal of the California law that bans same-sex marriage and the other seeks to overturn the federal Defense of Marriage Act.
"I maintain to you that we lost the issue when we started allowing the word 'marriage' to be bastardized and redefined by simply adding words to it," Limbaugh said.
Limbaugh said discrimination against gay couples wasn't an issue because "no one sensible" is against denying same-sex couples "the rights of contract or inheritance or hospital visits."
"The issue has always been denying them a status that they can't have, by definition," he said. "By definition ... same-sex people cannot be married. So instead of maintaining that and holding fast to that, we allowed the argument to be made that the definition needed to change, on the basis that we're dealing with something discriminatory, bigoted, and all of these mystical things that it's not and never has been."