Definitions of single:

• noun:   a base hit on which the batter stops safely at first base
• noun:   the smallest whole number or a numeral representing this number
• verb:   hit a one-base hit
• adjective:   used of flowers having usually only one row or whorl of petals

  Example: "Single chrysanthemums resemble daisies and may have more than one row of petals"

• adjective:   not married or related to the unmarried state

  Example: "Sex and the single girl"

• name:  A surname (very rare: popularity rank in the U.S.: #54197)