Abarim Publications' online Biblical Greek Dictionary
The noun χηρα (chera) means widow. It stems from the same Proto-Indo-European root "geh-", to go or leave behind, as does our English verb to go (and the German gehen).
Although predominantly denoting a lady whose husband died, the classics would also use this word in a slightly broader sense, to describe general bereavement (specifically: a house bereaved of men), or even a dish without sauce (which reminds of the not-related but similar word ξηρα, xera, dry, as in a dry river bed or dry food as opposed to wine and oil).
In ancient languages, masculinity is the tendency to be individual whereas femininity is the tendency toward collectivity. This is why body parts of which there is one are usually masculine, whereas body parts that come in pairs are usually feminine. It's also the reason why God is masculine (God is one: Deuteronomy 6:4), and creation is feminine (creation consists of many creatures). The Hebrew word for people is the same as for mother, namely אם ('em), which means that Eve, the "mother" of all living, is what we moderns call the biosphere.
A king (or centralized government) is the masculine embodiment of the nation's constitutional law, whereas the people are the feminine embodiment of that same law. Our human world is of course positively crawling with kings without kingdoms: guys who know it all but can't get anybody to listen to them. The opposite is equally sad, namely a people whose king has died: whose law-giving and policy-making government has lost its ability to organically respond to the living nature of their ever evolving people.
A country whose laws are synchronous with the eternal laws of nature has no centralized government (but a decentralized self-government), and is thus the Bride of God (whose laws govern the whole of creation and never change). A country whose laws never change and are enforced from a central human government, is governed by a tombstone. That's a widow (Revelation 18:7).
Our noun χηρα (chera) occurs 27 times in the New Testament; see full concordance.