In the historical understanding - i.e. two women living together as a household, or even a family unit, but without the underlying romantic / sexual relationship.
Discussed it with an old friend (we know each other for 20+ years), firstly as a joke, but then it actually turned into a serious discussion... and then into planning. We used to flat-share during the student years, and then were often on-off coach-surfing at each other's places for a couple of weeks at a time, and just joked that it was the healthiest and the most pleasurable co-habitation experience both of us have ever had (including our marriages). We get along extremely well together, all our friendship teething problems are (hopefully) well in the past.
We both are single mothers in professional jobs (same industry too), our children are approximately same age and are good friends. The housing and childcare costs are crippling us both, and we both are very lonely. No intention from any of us to remarry or even live with a man again until our children are much older.
Any obvious drawbacks to the plan?