The word life has many meanings and uses. Too many, perhaps. The four-letter word can refer to (1) the duration of an individual’s existence, as in life-span, lifetime. It can mean (2) daily experiences, as in quality of life, making life easier. It can refer (3) to the state or characteristics of being animate, as in signs of life. And (4) it can mean all living things collectively, as in life on earth.

When two of these definitions fit into the same context, uncertainty results. If a survey asks, “How happy are you with your life?”, some respondents will rate the years they have lived thus far (definition 1) while other score their degree of happiness during a typical day in the present (2).

Similarly, If a sentence states that “Life on earth began 3.8 billion years ago,” is the reader to imagine a  glob of molecules that duplicates itself (3) or a first, single-celled, membrane-enclosed bacterium (4)? Maybe both.

Which label best covers them all: “organisms,” “beings,” “creatures,” “selves,” or “living things”?
(weed-science-classes.wikspaces.com)

Definition 4—living things collectively—may be a good candidate for replacement by a plain synonym. There is, surprisingly, no commonly accepted term except life that so smoothly takes in not just animals or plants or microbes but all of them. But let’s review some options.

Organisms might serve, but not very well. Dating from the 18th century, organism can refer to any living thing, but its focus is on structures and systems. (It is related to organization.) Organisms has its place in the laboratory, but it doesn’t work well for broad musings on the totality of living things. If your perspective is poetic, a sentence such as “I marveled at the wonders of the organisms in the fields” lacks something.

Beings would seem to fit the bill. It’s familiar and seems broad enough.  It has spiritual dignity. But it is oriented around humans. Although Webster’s includes “living things” as one of its definitions, in common use it does not evoke plants and microbes. It might seem odd to refer to the vegetables growing in the garden as beings.

The same goes for creature, as in “Interesting creatures filled the forest.” “Creatures“ seem animal. They walk, fly, swim, or slither; they don’t put down roots or bloom.

Significantly, like beings, creatures came into use six centuries ago when plants and animals occupied separate categories of natural philosophy.

In contrast, a recent coinage from some scientists is selves, since living things, even a microbe, move towards food, avoid harm, repair themselves, and reproduce. Inanimate things don’t. I hope the usage catches on, but it hasn’t yet.

In lieu of single-word synonyms for life in the sense of totality of organisms, some phrases include the living world and the world of life. My preference so far, though, is living things. (I used it in the paragraph just above.) It’s clunky, and it’s almost an oxymoron. But it points to all things living and to nothing else.

There is another meaning of the word life that I think needs separating out. This is sense number 3, “the state or characteristics of being animate.” We have no noun to label the quality of being alive in the same way that we can use death to label the quality of being dead. We have alive of course as an everyday and precise adjective, but we don’t have a good noun version of it.

An example of the use of “livingness” by sculptor Louise Nevelson
(izquotes.com)

There is aliveness, which appears in descriptions of art and fashion. It means that something has exuberance and vitality. But its main use is to hype a product; it rarely if ever refers just to the state of being alive.

I use livingness. It is a rare but real word; you can look it up. True, it’s bland and clunky. But it’s effective at naming the characteristic at hand. I’ll stick with it for now.

So: living things and livingness may be useful to sharpen the focus on two meanings of life – If that’s what we want to do. The profusion of meanings of the word probably reflects how intertwined for many people those meanings are, and generally the speakers of a language have the words that they need in order to talk about what they want to talk about in the way they want to talk about it. But we could discuss a big topic like life more easily if we could separate out some meanings when we needed to.