alphabet soup

Short definition from Wiktionary

Noun

1. 1
   A type of soup that contains noodles in the shape of various alphabetical letters, sometimes also numbers.
2. 2
   A cryptic overabundance of acronyms and abbreviations.
3. 3
   A quantity of people or organizations that are referred to by acronyms.
4. 4
   A physical state in which there is a miscellany of different particles, often designated by letters.
5. 5
   The series of preliminary races (denoted by letters) through which drivers must advance to the main event.