1.  option(n = noun.possession) - the right to buy or sell property at an agreed price; the right is purchased and if it is not exercised by a stated date the money is forfeited;
is a kind of derivative, derivative instrument
has particulars: naked option, covered option, call, call option, put, put option, straddle, incentive option, incentive stock option, stock option, lock-up option

2.  option(n = noun.cognition) alternative, choice - one of a number of things from which only one can be chosen; "what option did I have?"; "there no other alternative"; "my only choice is to refuse"
is a kind of deciding, decision making
has particulars: obverse, druthers, preference, default, default option, opening, possibility, possible action, impossibility, impossible action, hobson's choice, soft option

3.  option(n = noun.act) choice, pick, selection - the act of choosing or selecting; "your choice of colors was unfortunate"; "you can take your pick"
is a kind of action
has particulars: casting, coloration, colouration, sampling, conclusion, decision, determination, volition, willing, election, ballot, balloting, vote, voting
Derived form verb opt₁

1.  The power of choosing; the right of choice or election; an alternative. [1913 Webster]
"There is an option left to the United States of America, whether they will be respectable and prosperous, or contemptible and miserable, as a nation." [1913 Webster]

2.  The exercise of the power of choice; choice. [1913 Webster]
"Transplantation must proceed from the option of the people, else it sounds like an exile." [1913 Webster]

3.  A wishing; a wish. Bp. Hall. [1913 Webster]

4.  A right formerly belonging to an archbishop to select any one dignity or benefice in the gift of a suffragan bishop consecrated or confirmed by him, for bestowal by himself when next vacant; -- annulled by Parliament in 1845. [1913 Webster]

5.  A stipulated privilege, given to a party in a time contract, of demanding its fulfillment on any day within a specified limit; also, the contract giving that privelege; as, an option to buy a stock at a given price; to exercise an option. [1913 Webster]
" A person owning a stock may sell to another person an option or right to buy that stock at some specified price within a specified period of time, and in return will get a premium in consideration for giving the option. If the option price (the strike price) is above the market value for the entire period in which the option is valid, the option is typically not exercised, and expires with no need on the part of the stock owner to transfer the actual stock itself. If however the stock price rises above the option price, the holder of the option may exercise the option, and buy the stock at the specificed price, and may in turn resell the stock at the current market value, perhaps making a net profit on the transaction. The original holder of the stock will receive, in addition to the price at which the stock is sold, the price of the option, and will generally receive more money than if the stock itself were sold at the time that the option was sold. The actual profits for the transaction will depend on the fees that brokers charge for conducting the sales of options and stocks." [PJC]

option, n.
1 a the act or an instance of choosing; a choice. b a thing that is or may be chosen (those are the options).
2 the liberty of choosing; freedom of choice.
3 Stock Exch. etc. the right, obtained by payment, to buy, sell, etc. specified stocks etc. at a specified price within a set time.

Idiom:
have no option but to must. keep (or leave) one's options open not commit oneself.

Etymology:
F or f. L optio, stem of optare choose

N  will, volition, conation, velleity, liberum arbitrium, will and pleasure, free will, freedom, discretion, option, voluntariness, spontaneity, spontaneousness, originality, pleasure, wish, mind, desire, frame of mind, intention, predetermination, selfcontrol, determination, force of will, voluntary, volitional, willful, free, optional, discretional, discretionary, volitient, volitive, minded, prepense, intended, autocratic, unbidden &c (bid), spontaneous, original, unconstrained, voluntarily, at will, at pleasure, a volonte, a discretion, al piacere, ad libitum, ad arbitrium, as one thinks proper, as it seems good to, a beneplacito, of one's won accord, of one's own free will, proprio motu, suo motu, ex meromotu, out of one's won head, by choice, purposely, deliberately, stet pro ratione voluntas, sic volo sic jubeo, a vostro beneplacito, beneficium accipere libertatem est vendere, Deus vult, was man nicht kann meiden muss man willig leiden.

N  choice, option, discretion, preoption, alternative, dilemma, embarras de choix, adoption, cooptation, novation, decision, election, political election (politics), selection, excerption, gleaning, eclecticism, excerpta, gleanings, cuttings, scissors and paste, pick, preference, prelation, opinion poll, survey, predilection, optional, discretional, eclectic, choosing, preferential, chosen, choice, optionally, at pleasure, either the one or the other, or at the option of, whether or not, once and for all, for one's money, by choice, by preference, in preference, rather, before.

N  possession, seizin, seisin, ownership, occupancy, hold, holding, tenure, tenancy, feodality, dependency, villenage, villeinage, socage, chivalry, knight service, exclusive possession, impropriation, monopoly, retention, prepossession, preoccupancy, nine points of the law, corner, usucaption, future possession, heritage, inheritance, heirship, reversion, fee, seigniority, primogeniture, ultimogeniture, futures contract, warrant, put, call, option, right of first refusal, bird in hand, uti possidetis, chose in possession, possessing, worth, possessed of, seized of, master of, in possession of, usucapient, endowed with, blest with, instinct with, fraught with, laden with, charged with, possessed, on hand, by one, in hand, in store, in stock, in one's hands, in one's grasp, in one's possession, at one's command, at one's disposal, one's own, unsold, unshared, entbehre gern was du nicht hast, meum et tuum, tuum est.

call option, covered option, default option, incentive option, incentive stock option, local option, lock-up option, naked option, put option, soft option, stock option