What is embroidery?

Embroidery is a craft of decorating a fabric or other materials with the help of needle to apply thread or yarn.

Sounds like what you know about embroidering has come from the first paragraph of the embroidery wiki page.

Embroidery is the fancy, fandangling flights of fantasm; the frou-froued, frivolous frippery attached to every thread.

This may resemble to wiki page but this is the definition I've read in my institute

1. This is a five year old thread from someone who had never come back to the forum since posting this;
2. Clearly, she was asking for embroidery ideas (patterns; techniques; styles; etc...) ... not an elementary school level definition

I would say it is an art created on materials using threads and needle.