"Developing countries" is the most common term I've seen for the countries that are less developed than other countries, both in the EA community and in broader discourse about international development. However, the term is controversial and vague. According to Abrahams (2019), "developing countries" doesn't refer to any particular criteria, and as the global development situation has changed, the category of "developing countries" has grown more heterogeneous:

If we look to other indicators, the picture has also become more complex as countries have advanced at different paces and in different ways, and we have come to acknowledge that the challenges of poverty and inequality are not restricted to specific corners of the world. Countries facing entirely different challenges are lumped together as “developing,” while countries in the “developed” category are hardly free of challenges themselves. The US is classified as developed by all major intergovernmental organisations, for example, and yet there are countries classified as developing that beat it on indicators around health care and connectivity. Meanwhile, more people in extreme poverty live in middle-income countries than in low-income countries.... Last but not least, our understanding of the relationships between countries has changed. Just as the terms “first world” and “third world” were eventually cast off as inappropriate, the colonial baggage of the terms “developed” and “developing” is increasingly being acknowledged.

Because of this, the World Bank has started referring to countries as "low-income," "middle-income," and "high-income" countries. On the other hand, some advocates of the term "developing countries" like it because it implies that more-developed countries have an obligation to assist less-developed countries.

Which terms do you use to describe more- and less-developed countries? Which terms do you think the EA community should use?