These structures are in essence made up by two identical
interconnected graphs representing one of the basic elements of
Western ideography, .
Ideographically, is a sign for one complete oscillation or one whole wave.
If we take the straight line as our graphic reference, then the complete wave of a guitar string when strummed, will move back and forth above and below the straight line, graphically (the sign for frequency). Consequently, represents all types of waves in Western ideography.
See in Group 18 for a strange medieval use of the sign .
In musical notation stands for grupetto, i.e. that one should play a group of four notes, the note above, the note itself, the note below, and the note itself.
In eighteenth-century chemistry meant solvere, to dissolve, and solutio, or solution.
In propositional logic, P means that the opposite of P is true.
In electrical contexts stands for alternating current.
In dictionaries stands for words that have been referred to earlier or indicates that a term or expression is interchangeable with another.
In mathematics can stand for varies as, is similar to, or is a complement of.
In Spanish and Portuguese writing used over certain letters indicates a certain pronunciation and is called tilde.
In meteorology has been, or is used to indicate ice or a coating of ice.
The latter is also drawn and .
In genealogical contexts and can mean baptized.