Jana!
I grow tons of herbs for our Master Gardeners group every year, as well as for my own garden. My interests are mainly for culinary herbs, but also use some medicinally as well.
Bonehead is correct that the definition of herbs is very broad. This is from the Herb Society of America website:
According to The Herb Society of America's New Encyclopedia of Herbs and Their Uses by Deni Bown:
"The term "herb" also has more than one definition. Botanists describe an herb as a small, seed bearing plant with fleshy, rather than woody, parts (from which we get the term "herbaceous"). In this book, the term refers to a far wider range of plants. In addition to herbaceous perennials, herbs include trees, shrubs, annuals, vines, and more primitive plants, such as ferns, mosses, algae, lichens, and fungi. They [herbs] are valued for their flavor, fragrance, medicinal and healthful qualities, economic and industrial uses, pesticidal properties, and coloring materials (dyes)."
Some past herbs of the year (determined by the International Herb Society) have included: elderberry, horseradish, calendula, bay, artemesia. This year it is pepper (capsicum).