harden

Short definition from Wiktionary

Verb

1. 1
   To become hard.
2. 2
   To make something hard or harder.
3. 3
   To strengthen.
4. 4
   To modify (a website or other system) to make it resistant to malicious attacks.
5. 5
   To become or make (a person or thing) resistant or less sensitive.
6. 6
   To get an erection.
7. 7
   To become or make (a consonant) more fortis; to (cause to) undergo fortition.
8. 8
   To unpalatalize or velarize.

Noun

1. 1
   Alternative form of hurden (“coarse linen”).

Proper noun

1. 1
   A surname.
2. 2
   A place name: A suburb in the Metropolitan Borough of Walsall, West Midlands, England (OS grid ref SK0101).
3. 3
   A place name: A village and civil parish (with a village council) in the Metropolitan Borough of Bradford, West Yorkshire, England (OS grid ref SE0838).
4. 4
   A place name: A town in Hilltops council area, southern New South Wales, Australia.