Wood was paired with the Horse in the Chinese zodiac year that began on January 31, 2014.
That year is commonly called the Wood Horse year. The Chinese zodiac combines a twelve-animal cycle with the five elements—Wood, Fire, Earth, Metal, and Water. The element is determined through the heavenly-stem part of the traditional sexagenary cycle.
The 2014 zodiac year lasted until the day before the next Lunar New Year in 2015. It was therefore not simply the same as the Gregorian calendar year 2014 from January through December.
The next Horse year occurs twelve years later, but it is not another Wood Horse year. The same animal-element combination returns after 60 years, because the animal cycle and element cycle must realign. This is why Chinese calendrical terms can be more precise than saying only “Year of the Horse.”