How do you define friendship?

In a world ruled by social media, where the word "friend" now exists as both a label and a verb, the definitions have become multifaceted...if not downright confusing.

That fact was highlighted by a recent study published in the journal PLOS One, entitled: "Are You Your Friends' Friend? Poor Perception of Friendship Ties Limits the Ability to Promote Behavioral Change."

As reported by the New York Times:

"The study analyzed friendship ties among 84 subjects (ages 23 to 38) in a business management class by asking them to rank one another on a five-point continuum of closeness from 'I don't know this person' to 'One of my best friends.' The feelings were mutual 53 percent of the time while the expectation of reciprocity was pegged at 94 percent. This is consistent with data from several other friendship studies conducted over the past decade, encompassing more than 92,000 subjects, in which the reciprocity rates ranged from 34 percent to 53 percent."

In other words, a significant portion of the people you call "friend" wouldn't say the same about you. Conversely, someone with whom you feel very little connection just may consider you a BFF.

When it comes to our work lives, the situation becomes even more clouded. For example, when introducing a close colleague to your significant other, you might refer to him or her as "a friend from work." Sure, that description gives context to the relationship. But it also sets a boundary.

We hear a lot of talk today about work/life balance, but what we see is work spilling more and more into personal life, and vice-versa. For example, organizations strive to improve team spirit through extracurricular activities. Many companies follow the "Google model" in providing perks such as dining halls, fitness centers, and recreation rooms to employees. The idea is if colleagues eat, exercise and play together--they'll work better together.

Of course, not everyone wants work and personal life to overlap--and neither do they consider their colleagues as close friends. (The same goes for your clients, suppliers, and other business partners.) But how can you best handle that situation? Making your feelings known, even diplomatically, may result in your being viewed as an outcast. At best, you run the risk of receiving the dreaded "doesn't play well with others" label--which can greatly affect your workplace relationships, or even your career prospects.

As one who has encountered this situation, I've learned that following a single principle has worked best:

Be friendly to everyone. But choose your friends carefully.

Of course, this is easier said than done--and as the research indicates, misunderstandings are sure to arise.

Which begs me to repeat the question:

How do you define friendship?

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A version of this article originally appeared on Inc.com.