Spice

A spice is a dried seed, fruit, root, bark or vegetative substance used in nutritionally insignificant quantities as a food additive for the purpose of flavoring, and sometimes as a preservative by killing or preventing the growth of harmful bacteria.

Many of these substances are also used for other purposes, such as medicine, religious rituals, cosmetics, perfumery or eating as vegetables. For example, turmeric is also used as a preservative; licorice as a medicine; garlic as a vegetable. In some cases they are referred to by different terms.
In the kitchen, spices are distinguished from herbs, which are leafy, green plant parts used for flavoring purposes. Herbs, such as basil or oregano, may be used fresh, and are commonly chopped into smaller pieces. Spices, however, are dried and often ground or grated into a powder. Small seeds, such as fennel and mustard seeds, are used both whole and in powder form.

Salt is a very common seasoning. Because of its granular form, it is often mistakenly considered to be a spice. It is in fact a mineral product.
The basic classification of spices is as follows:
Leaves and/or branches of aromatic plants; all or part of the plant can be used. Examples include basil, bay leaf, parsley, rosemary, tarragon, and thyme, oregano, chervil.
Ripened fruits or seeds of plants. Examples include dill, fennel, coriander , fenugreek , berberis , mustard, and black pepper.
Roots or bulbs of certain plants. Examples include garlic, onion, celery and ginger.