As a noun arrondissement

is an administrative division in some French- or Dutch-speaking countries.

As a proper noun Saintes is

a city in the southeastern French département Charente-Maritime, the former capital of the Saintonge province.

As proper nouns the difference between caribbean and saintes

is that caribbean is the Caribbean Sea while Saintes is a city in the southeastern French département Charente-Maritime, the former capital of the Saintonge province.

As an adjective Caribbean

is pertaining to the sea and region of the western Atlantic bounded by South America, Central America, and the islands of the West Indies (such as Cuba and Hispaniola).

Megasporic is a related term of megasporangium.

As a noun megasporangium is

(biology) a sporangium which produces only megaspores.

Megasporogenesis is a related term of megasporangium.

As nouns the difference between megasporogenesis and megasporangium

is that megasporogenesis is the formation of megaspores in angiosperms while megasporangium is (biology) a sporangium which produces only megaspores.

Megasporangium is a related term of sporangial.

As an adjective sporangial

is relating to the sporangium.

As a noun megasporangium is

a sporangium which produces only megaspores.

Megasporangium is a related term of sporangiophore.

As nouns the difference between sporangiophore and megasporangium

is that sporangiophore is the axis or receptacle in certain ferns (such as Trichomanes), which bears the sporangia while megasporangium is a sporangium which produces only megaspores.

Spore is a related term of megasporangium.

As nouns the difference between spore and megasporangium

is that spore is spore while megasporangium is (biology) a sporangium which produces only megaspores.

As nouns the difference between half and semicircumference

is that half is one of two usually roughly equal parts into which anything may be divided, or considered as divided; — sometimes followed by of; as, a half of an apple while semicircumference is one half of the circumference of a circle.

As an adjective half

is consisting of a moiety, or half (1/2, 50%).

As an adverb half

is in two equal parts or to an equal degree; in some part approximating a half; partially; imperfectly.

As a verb half

is to halve.

As a preposition half

is a half-hour after, thirty minutes after used with the number of the hour.

As nouns the difference between circumference and semicircumference

is that circumference is (geometry) the line that bounds a circle or other two-dimensional figure while semicircumference is one half of the circumference of a circle.

As a verb circumference

is (obsolete|transitive) to include in a circular space; to bound.

As nouns the difference between circle and semicircumference

is that circle is (lb) a two-dimensional geometric figure, a line, consisting of the set of all those points in a plane that are equally distant from another point while semicircumference is one half of the circumference of a circle.

As a verb circle

is to travel around along a curved path.