Chemistry - French

French in its formal sense and used in its capitalized form, denotes:

Something from or related to France. The French city of Paris has many fine restaurants.
Something from or related to Île-de-France, such as the area of French Brie as opposed to Champagne Brie.
The French language. An official language in France, Canada, Belgium, Switzerland, and many other countries.
The French people. See: List of French people.
3 times the outer diameter (measured in mm) of a tube (abbreviated "Fr"). Notice that this approximately equals the outer circumference of a tube, which is exactly its outer diameter times pi. One can therefore define the unit length Fr = mm/3 under the stipulation that it only be applied to diameters. French units are used primarily for catheters. In catheter specifications, outer diameter is often abbreviated "OD" and given in inches or mm.
The French River (Ontario).
A surname, e.g., Daniel Chester French, David French, John French, Samuel French Inc. , Victor French.
French Creek, a creek in the town of French Creek, New York.

The uncapitalized (sometimes capitalized) word french has various connotations:

To cut into strips for cooking in the French style (also known as: to julienne), e.g., frenched carrots. The term french fries is a further simplification from this meaning applied specifically to potatoes.
To remove fat and meat from the tips of a bone-in chop or roast, e.g., frenched rack of lamb.

The word also appears in many short phrases such as french doors, french horn, french toast, french letter, french leave, french kiss, etc., coined to imply origination in or association with France, not necessarily accurately. (Many of them are disrespectful.) Some of them sometimes have the initial f capitalized.

There are similar expressions in France, but referring to England. "French cream" (a sweet milky sauce for desserts like cakes) is called in French "crème anglaise" (English cream). Some of these French expressions, such as "capote anglaise," "filer à l'anglaise," or "le vice anglais," are also disrespectful. The same pattern can be found while speaking of Belgium, another country that borders France.