President-elect Donald Trump has been proclaiming that the election gave him "a clear mandate." Vice-President-elect Mike Pence says Republicans will repeal the Affordable Care Act, claiming that the voters gave them a mandate to overturn Obamacare. Neither statement is true.
The strict definition of mandate is: an official order to carry something out. In the case of an election, the winner has a mandate to perform the functions of the office. But, by common usage, citing an election as a mandate to pass certain controversial legislation requires winning by a rather large amount. Merriam-Webster Dictionary gives this definition: "A mandate is an official command or a go-ahead. When a politician wins an election by a wide margin, that's a mandate to implement her ideas."
The Republican ticket of Trump-Pence won office by getting more than 50% of the 538 electoral votes, i.e. at least 270 (Trump got 306) and being affirmed by the Electoral College as the winners. But 306 out of 538 is not "a wide margin," even if you're only considering electoral votes.
In my opinion, you could never call it a mandate when your opponent won the popular vote, and certainly not when she got 2.7 million more votes than you did.
So, no, Mr. Trump and Mr. Pence, you did not win a mandate, no matter how many times you say it.