WASHINGTON — An unusual coalition of Supreme Court justices joined Thursday to rule in favor of an immigrant fighting deportation in a case that the court said turned on the meaning of the shortest word, “a.”

By a 6-3 vote, the court sided with Agusto Niz-Chavez, a Guatemalan immigrant who has been in the United States since 2005. Eight years later, he received a notice to appear at a deportation hearing but this notice did not include a date or time. Two months after that, a second notice instructed him when and where to show up.

By sending notice of a deportation hearing, the government can stop the clock on immigrants hoping to show they have been in the United States for at least 10 straight years. The 10-year mark makes it easier under federal law to ask to be allowed to remain in the country.