ありPossibility, To have, With

あり itself is the literary form of the う-Verb 有(あ)る 'to be', and is used in a similar way to なし. However, rather than meaning that something is 'without (A)', it shows that something is 'with (A), amongst other things'. This 'amongst other things' is important, as あり will primarily be used when something is being presented as a single possibility among many possibilities.

あり can be and often is used simply as a reply to a statement to indicate agreement, or that the listener thinks that what the speaker is saying is possible.

Caution

Occasionally, the kanji 在(あ)る may sometimes also be used. Although the difference between these two kanji is slight, 有(あ)り indicates 'inclusiveness as part of a whole', while 在(あ)り focuses more on 'stand-alone existence'.