Arc

Noun:

1. Electrical conduction through a gas in an applied electric field
2. A continuous portion of a circle
3. Something curved in shape

Usage:
Verb:

1. Form an arch or curve
2. Form an electrical arc

Usage: 

1. "her back arcs"

Synonyms:

1. Arch
2. Bow
3. Curve
4. Discharge
5. Electric Arc
6. Electric Discharge
7. Spark

Boldface

Noun:

1. A typeface with thick heavy lines

Usage:

1. Print in boldface

Synonyms:

1. Bold
2. Bold face