incidental

American  

[in-si-den-tl] / ˌɪn sɪˈdɛn tl /

adjective

1. happening or likely to happen in an unplanned or subordinate conjunction with something else.

   Synonyms:

   contingent, fortuitous, chance, casual

   Antonyms:

   fundamental

2. incurred casually and in addition to the regular or main amount.

   incidental expenses.

3. likely to happen or naturally appertaining (usually followed byto ).

---

noun

1. something incidental, as a circumstance.

2. incidentals, minor expenses.

incidental British  

/ ˌɪnsɪˈdɛntəl /

adjective

1. happening in connection with or resulting from something more important; casual or fortuitous

2. found in connection (with); related (to)

3. caused (by)

4. occasional or minor

   incidental expenses

---

noun

1. (often plural) an incidental or minor expense, event, or action

Other Word Forms

• incidentalness noun
• nonincidental adjective
• nonincidentally adverb
• unincidental adjective
• unincidentally adverb

Etymology

Origin of incidental

First recorded in 1610–20; incident + -al ¹

Explanation

Incidental means secondary in time or importance. If you lose weight because you moved and must walk further to school, the weight loss was incidental to the move. When something is incidental, it is never the main thing. It's okay to include incidental details as they can add depth to your storytelling, but they are never crucial to the story. A company might pay your main expenses when you travel for business but will probably not reimburse you for the incidental ones. The music you hear between acts of a play is called incidental. It's not crucial to the action, but it makes the waiting easier.

Example Sentences

People are incidental to Godzilla’s destructive marches through cities or transoceanic swims.

From Salon • Mar. 20, 2026

Generally, the deduction is designed for expenses that are incidental to research and development, such as rent, utilities and other overhead.

From Barron's • Mar. 14, 2026

The net effect: Nvidia can afford to dial back its earnings spin, because the expense on its income statement for stock-based pay is incidental compared with its true economic cost.

From The Wall Street Journal • Mar. 4, 2026

His avaricious acquisitions of western lands is well known and not incidental to his desire to break from Great Britain, which had tried to limit western migration.

From Slate • Feb. 16, 2026

“Did I?” she replied, in an incidental and forgetful way.

From "Great Expectations" by Charles Dickens

Related Words

• accidental
• ancillary
• casual
• coincidental
• random
• secondary