Turn Periods are also used to indicate most abbreviated words such as, Mr. (Mister), Wed. ednesday), or Dec. (December)! However, they are not used with initials used in place of personal names(often written in capital letters or after metric abbreviations such as NASA(National Aeronautics and Space Administration), UNICEF(United Nations Children's Fund formerly United Nations International Children's Emergency Fund), kg(kilogram), and km(kilometer).