What is a noun for long?

There isn't a single perfect noun for "long" because it depends on the context. Here are some options, depending on what you mean by "long":

For length:

* Duration: This refers to the length of time something lasts.

* Extent: This refers to the length of a physical object or distance.

* Span: This refers to the length of time or space covered.

* Period: This refers to a specific length of time.

* Stretch: This refers to a continuous length of something.

* Length: This is the most direct and straightforward noun for "long."

For something that is long and thin:

* Strand: This refers to a single thin length of something, like hair or thread.

* Rope: This refers to a long, thick length of something that can be used for tying or pulling.

For something that is long and narrow:

* Strip: This refers to a long, narrow piece of something.

* Lane: This refers to a long, narrow path.

For something that is long and winding:

* Path: This refers to a long, winding route.

* Trail: This refers to a long, winding path through the wilderness.

For something that is long and drawn out:

* Process: This refers to a series of actions or events that take a long time.

* Protraction: This refers to the act of extending something in time.

The best noun to use depends on what you are trying to describe.