Yes, trade is playable
...and is worth 6 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Trade" Definition
noun
An exchange of one thing for another.
An occupation, especially one requiring skilled labor; craft: the building trades, including carpentry, masonry, plumbing, and electrical installation.
The act or an instance of buying or selling; transaction.
The business of buying and selling commodities; commerce. See Synonyms at business.
The customers of a specified business or industry; clientele.
adjective
Of or relating to books that are primarily published to be sold commercially, as in bookstores.
Of or relating to trade or commerce.
Relating to, used by, or serving a particular trade: a trade magazine.
Of, relating to, or used in trade.
Intended for or limited to persons in a business or industry.
verb-intransitive
To be offered for sale: Stocks traded at lower prices this morning.
To engage in buying and selling for profit.
To make an exchange of one thing for another.
To shop or buy regularly: trades at the local supermarket.
verb-transitive
To buy and sell (stock, for example).
To give in exchange for something else: trade farm products for manufactured goods; will trade my ticket for yours.
To pass back and forth: We traded jokes.
phrasal-verb
Trade down To trade something in for something else of lower value or price: bought a new, smaller car, trading the old one down for economy.
Trade in To surrender or sell (an old or used item), using the proceeds as partial payment on a new purchase.
Trade on To put to calculated and often unscrupulous advantage; exploit: children of celebrities who trade on their family names.
Trade up To trade something in for something else of greater value or price: The value of our house soared, enabling us to trade up to a larger place.