My simple definitions

Meme/s- information which can be received, imitated, transmitted, varied, and replicated through and between cultural interactors.

Culture- The way in which things are done in a particular social context.

DISCLAIMER:  The term meme is a metaphor, a concept, made up by Richard Dawkins, and used by people, as a linguistic tool for accounting for and talking about a very complex and pervasive phenomenon, which has observable effects, but no empirically distinguishable physicality.  I have many qualms myself with memetic models and selfish genes, and all of that.  I dont particulatly care for the tendency to conceptualize a meme as a measurable unit. If it you just cant get over an aversion to the language of memes and memetics, or scientific jargon generally, I think a case could be made for replaceing the word meme with spirit if that makes you feel better.  I think that you could use language of memes or of spirits and still be trying to articulate the same sort of thing, entity, process, phenomenon.... and either might be more or less viable or useful, depending on the context in which its used.  One isn't true or false, but either one is true enough to help expedite communication with those who embrace and think with which ever liguistic/conceptual framework.

I find the word meme to be a useful word for communicating something that might be otherwise hard to articulate, like many other words which I think may be easily conceptually misrepresented upon apprehension (or illusion thereof).   Not the best tools possible in every case, but the ones I can use in a western-secular-achedemic-jargon context.   

Like freudian metaphors for "mental life" in the early 20th century, memetic metaphors for cultural transmission and replication are helpfull for our conceptual and communicative purposes in the meanwhile, but we must always be looking to improve the clarity and utility of the words we use, and how we use them.  We should plan for and work towards the obelecence or trancendence of incomplete models, as all models are incomplete.

SOME COMMON DEFINITIONS OF THE WORD: MEME 

American Heritage Dictionary - meme- A unit of cultural information, such as a cultural practice or idea, that is transmitted verbally or by repeated action from one mind to another.

Dictionary.com Unabridged (v 1.0.1) - meme a cultural item that is transmitted by repetition in a manner analogous to the biological transmission of genes.

WordNet - meme n : a cultural unit (an idea or value or pattern of behavior) that is passed from one generation to another by nongenetic means (as by imitation); "memes are the cultrual counterpart of genes"

Free On-line Dictionary of Computing -

/meem/ [By analogy with "gene"] Richard Dawkins's
term for an idea considered as a replicator, especially with
the connotation that memes parasitise people into propagating
them much as viruses do.

Memes can be considered the unit of cultural evolution. Ideas
can evolve in a way analogous to biological evolution. Some
ideas survive better than others; ideas can mutate through,
for example, misunderstandings; and two ideas can recombine to
produce a new idea involving elements of each parent idea.

The term is used especially in the phrase "meme complex"
denoting a group of mutually supporting memes that form an
organised belief system, such as a religion. However, "meme"
is often misused to mean "meme complex".

Use of the term connotes acceptance of the idea that in humans
(and presumably other tool- and language-using sophonts)
cultural evolution by selection of adaptive ideas has become
more important than biological evolution by selection of
hereditary traits. Hackers find this idea congenial for
tolerably obvious reasons.

See also memetic algorithm.

Jargon File-  meme- /meem/ n. [coined by analogy with `gene', by Richard
Dawkins] An idea considered as a replicator, esp. with the
connotation that memes parasitize people into propagating them much
as viruses do. Used esp. in the phrase `meme complex' denoting a
group of mutually supporting memes that form an organized belief
system, such as a religion. This lexicon is an (epidemiological)
vector of the `hacker subculture' meme complex; each entry might be
considered a meme. However, `meme' is often misused to mean `meme
complex'. Use of the term connotes acceptance of the idea that in
humans (and presumably other tool- and language-using sophonts)
cultural evolution by selection of adaptive ideas has superseded
biological evolution by selection of hereditary traits. Hackers
find this idea congenial for tolerably obvious reasons.