What is rd?

It appears your request is a bit vague. "RD" can refer to multiple things depending on the context. Here are a few possibilities:

1. RD as Registered Dietitian: A Registered Dietitian (RD) is a food and nutrition expert who has met the academic and professional requirements to qualify for the credential "RD." They provide guidance and education on nutrition and dietary modifications to help people manage diseases and promote overall health.

2. RD in Technology (Research and Development): In the context of technology and business, RD often stands for Research and Development. This refers to the activities companies undertake to innovate and introduce new products and services. It is a crucial component of a business's growth strategy.

3. RD as in "R&D" for Research and Development: In academia and corporate environments, R&D is a standard abbreviation for Research and Development, which focuses on innovating and improving products or services.

4. RD in Real Estate (Rural Development loans): The term RD can also refer to Rural Development loans, which are a type of government-backed mortgage offered by the U.S. Department of Agriculture (USDA) for individuals looking to buy homes in rural areas.

5. RD in Date and Time (Relative Date): Sometimes, RD can refer to relative dating, meaning a date given in terms relative to another date, often calculated from the present.

If you can provide more context, I can give more specific information.