Bug

1. An insect of the order Hemiptera (the “true bugs”).
2. Any of various species of marine or freshwater crustaceans; e.g. a Morton Bay bug, mudbug.
3. Any insect, arachnid, or other terrestrial arthropod that is a pest.

   These flies are a bother. I’ll get some bug spray and kill them.

4. Any insect, arachnid, myriapod or entognath.
5. (chiefly computing and engineering jargon) A problem that needs fixing.

   The software bug led the computer to calculate 2 plus 2 as 3.

6. A contagious illness; a bacterium or virus causing it

   He’s got the flu bug.

7. An enthusiasm for something; an obsession

   I caught the skiing bug while staying in the Alps.

8. A keen enthusiast or hobbyist.
9. A concealed electronic eavesdropping or intercept device

   We installed a bug in her telephone.

10. A small and usually invisible file (traditionally a single-pixel image) on a World Wide Web page, primarily used to track users.

    He suspected the image was a Web bug used for determining who was visiting the site.

11. A small, usually transparent or translucent image placed in a corner of a television program to indicate what network or cable channel is televising it

    Channel 4's bug distracted Jim from his favorite show.

12. A manually positioned marker in flight instruments.
13. A semi-automated telegraph key.
14. Hobgoblin, scarecrow; anything that terrifies.
15. ("the bug") HIV.
16. A limited form of wild card in some variants of poker.
17. A trilobite.
18. A young apprentice jockey.

1. To annoy.

   Don’t bug me, I’m busy!

2. To install an electronic listening device or devices in.

   We need to know what’s going on. We’ll bug his house.

noun

A microfossil, particularly a foraminiferan.