What does reckless driving mean?

Reckless driving is defined under the laws of the State of Washington.   It has a very specific definition and means according to statute:

RCW 46.61.500
Reckless driving -- Penalty.

(1) Any person who drives any vehicle in willful or wanton disregard for the safety of persons or property is guilty of reckless driving. Violation of the provisions of this section is a gross misdemeanor punishable by imprisonment of not more than one year and by a fine of not more than five thousand dollars.

(2) The license or permit to drive or any nonresident privilege of any person convicted of reckless driving shall be suspended by the department for not less than thirty days.

Are there any other forms of reckless driving (other than racing)?

Yes "embracing" while driving is also a crime.  According to statute, you may not "embrace" another person while that person is driving.

Here is that law:

RCW 46.61.665
Embracing another while driving.

It shall be unlawful for any person to operate a motor vehicle upon the highways of this state when such person has in his or her embrace another person which prevents the free and unhampered operation of such vehicle. Operation of a motor vehicle in violation of this section is prima facie evidence of reckless driving.