ひとつ
Meanings
Numeric
1. one
Noun
2. for one thing
often used in itemized lists
3. only
after a noun
4. (not) even
with a verb in negative form
Adverb
Noun
5. just (e.g. "just try it")
Adjective (の)
6. some kind of; one type of
Pitch accent
Top 1400
Composed of
one; one
Used in vocabulary (44 in total)
another; one more; not quite; not very good; lacking
one-by-one; separately; in detail
Examples (145 in total)
One is blue.
That was the last one.
That's one possibility.