triangle
Well, isn't a rectangular prism a geometric shape? And isn't a brick a rectangular prism? see this is one way that geometric shapes are used in architecture.
geometric
The nine-candle holder at Christmas is called a Menorah. It is used for Hanukkah. The ninth holder is called a Shamash.
There isn't one. The holidays are entirely different. The closest you could come is a candle, but a single candle does not represent Hanukkah. You can't use a star either, because a star has nothing to do with Hanukkah.
'Geometric' is an adjective, as it is used to describe something, e.g. a geometric shape. It is based on the noun 'geometry'.
The geometric shape used in truss bridges is the triangle.
F is not a geometric shape that is used. The standard geometric term vertex means the intersection point of two sides of a plane figure. If F is meant to represent figure this term might apply.
clothoid/ klothoid
Jews don't celebrate anything instead of Christmas. This is because Jesus plays no role whatsoever in Judaism, therefore there is no Jewish holiday to celebrate him. Some people mistakenly believe that Channukah is the "Jewish Christmas", however, this couldn't be further from the truth. Channukah celebrates the rejection of forced assimilation, celebrating Christmas would directly violate the meaning of Channukah.
A geometric figure is a shape like a square or rectangle and it can be used in different views like 3D, 2D and 1D would be just a line. So there is your answer!
Hanukkah can be used as an adjective or a noun.