か

1

indicates a question (sometimes rhetorical)

Note: was written as 歟; used at sentence-end

2

or; whether or not

Note: after each alternative

3

some- (e.g. something, someone)

Note: after an interrogative

See also: 何か

4

indicates doubt, uncertainty, etc.

Note: sometimes after other particles

See also: とか

5

emphatic prefix

Note: usu. before an adjective

See also: か弱い

6

suffix forming adjectives or adverbs

Note: after an indeclinable word

See also: 定か

7

in that way

Note: archaism