AA is a coffee grading term that refers to a specific, larger than normal, bean size. Kenya AA coffee beans, for example, pass through Grade 18 (18/64" diameter) sieve perforations, but are too large to pass through Grade 16 (16/64" diameter) sieve perforations. AA+ refers to coffee beans AA or larger. The term AA is used as a coffee quality "grade" due to the general correlation (with many exceptions) between coffee bean size and coffee flavor.  

Altura means height in Spanish and is used to describe high grown, or mountain grown, coffee.  

Excelso is used mostly as a coffee grading term, especially in Colombia. Excelso coffee beans are large, but slightly smaller than Supremo coffee beans. Excelso coffee beans pass through Grade 16 (16/64" diameter) sieve perforations, but are too large to pass through Grade 14 (14/64" diameter) sieve perforations. The term "Excelso" is used as a coffee quality "grade" due to the general correlation (with many exceptions) between coffee bean size and coffee flavor. Colombia Supremo coffee beans are slightly larger than excelso beans and will pass through Grade 18 (18/64" diameter) sieve perforations, but are too large to pass through Grade 16 perforations. Supremo and Excelso coffee beans may come from the same tree, but are sorted by size.  

Grade is generally used to indicate coffee bean size, which is associated with coffee quality. While there are many exceptions, coffee beans grown at higher elevations tend to be denser, larger, and have better flavor. The process of determining coffee bean size, or grading, is done by passing unroasted beans through perforated containers, or sieves. For example, Grade 18 beans, also called AA, will pass through a sieve with 18/64" diameter holes, but are retained by the next smaller sieve with 16/64" diameter holes. Traditionally, even grades were used for Arabicas (20, 18, 16, etc), and odd numbers were used for Robustas (17, 15, 13, etc). The method of grading coffee (classifying coffee quality) varies by country, and may include bean size, bean density, number of defects, growing altitude, taste, etc.  

Synonymous with "high grown (HG)", "hard bean (HB)" refers to coffee grown at altitudes about 4,000 - 4,500 feet above sea level. Beans grown at high altitudes mature more slowly and grow to be harder and denser than beans grown at lower elevations. The inherent consistency and taste attributes of high grown beans makes them more desirable, and generally more expensive, than coffees grown at lower elevations.   

Synonymous with "strictly high grown (SHG)", "strictly hard bean (SHB)" usually refers to coffee grown at altitudes higher than about 4,500 feet above sea level. Beans grown at high altitudes mature more slowly and grow to be harder and denser than beans grown at lower elevations. The inherent consistency and taste attributes of high grown beans makes them more desirable, and generally more expensive, than coffees grown at lower elevations.   

Strictly Soft (SS) beans are grown at relatively low altitudes (under 4,000 feet). Beans grown at lower altitudes mature quickly and produce a lighter, less dense bean. Strictly Soft Arabica beans have a more rounded flavor compared to the generally more flavorful and dense Arabica beans grown at higher elevations.  

Used mostly as a coffee grading term in Colombia. Supremo coffee beans are slightly larger than Excelso beans and will pass through Grade 18 (18/64" diameter) sieve perforations, but are too large to pass through Grade 16 perforations. Supremo and Excelso coffee beans may come from the same tree, but are sorted by size. Excelso coffee beans are also large, but slightly smaller than Supremo coffee beans. Excelso coffee beans will pass through Grade 16 (16/64" diameter) sieve perforations, but are too large to pass through Grade 14 (14/64" diameter) sieve perforations. The term "Supremo" is used as a coffee quality "grade" due to the general correlation (with many exceptions) between coffee bean size and coffee flavor.