Solution

SIGMA

2 clues

Greek letter

Word class: Common noun
Nature of clue: Description
Difficulty: Easy
Sources: Boatload Puzzles
Topics: Languages - Writing Systems, Maths Physics
From which decade: Older times

Other solutions to Greek letter

Summation symbol

Word class: Common noun
Nature of clue: Description
Difficulty: Medium
Sources: Boatload Puzzles
Topics: Maths Physics

Words are categorized by artificial intelligence: there can be mistakes.