coma

A serious condition in which someone is unconscious for a long time and cannot be woken.

• He is in a coma.
• She woke from a coma yesterday.
• The injury left him in a coma for months.

How to use it: go into a coma (He went into a coma after the accident.); be in a coma (She was in a coma for three weeks.)

Common phrases: in a coma, coma patient

The cloud of gas and dust around the central part of a comet.

• The comet has a bright coma.
• Sunlight made the coma easier to see.
• The telescope revealed dust within the coma.

Common phrases: comet coma, bright coma

A fault in a lens or mirror that makes points of light look stretched, like small tails.

• This lens shows noticeable coma.
• Coma makes stars near the image edge look stretched.
• The new mirror design reduces coma.

Similar words: comatic aberration

Common phrases: optical coma, reduce coma

A bunch of branches, leaves, or hairs at the top or end of a plant part.

• The seed has a silky coma.
• A coma of leaves tops the stem.
• The botanist examined the hairs in the coma.

Similar words: tuft

Common phrases: terminal coma, seed coma