A Sweetheart or a Card From a Sweetheart
This page is the CodyCross answer for the clue below from Physics, Group 1882, Puzzle 3 (Interstellar Medium).
Question is: A Sweetheart or a Card From a Sweetheart
and the answer is: VALENTINE
Word Meaning:
VALENTINE — An expression of affection, especially romantic affection, usually in the form of greeting card, gift, or message given the object of one's affection, especially on February 14th.
Definitions from Wiktionary.