Determinate or indeterminate? Hybrid or heirloom? Here is a tomato glossary to help you understand terms related to growing tomatoes. The list is in alphabetical order.

AAS (All-American selections): New varieties which are annually voted to be most superior.

Beefsteak: A term used to classify tomatoes that centers on the size and shape of the fruit. Beefsteaks are the largest type of tomato. Some beefsteak tomatoes weigh one pound or more. Beefsteak tomatoes are popular among home gardeners, particularly for making sandwiches, but are not often grown commercially because of the difficulty of processing.

Blight: Two diseases (early blight and late blight) that attack tomatoes and affect the leaves, stems, and fruit.

Cherry tomato: A term used to classify tomatoes that centers on the size and shape of the fruit. Cherry tomatoes are the smallest type of tomato. They range in size from a thumb tip to the size of a golf ball.

Cotyledons: The first leaves to emerge from the tomato seed.

Crack resistant: The characteristic of a tomato variety that inherently resists breaks in its skin. Breaks are sometimes called “growth cracks.” Cracks are usually caused by inconsistent watering or excessive rain. Concentric cracks are circles that span a section or the entire circumference of the tomato around the stem end of the fruit. Radial cracks are straight lines that extend outward and downward from the stem node.

Cultivar: A specific tomato type. The term “cultivar” is often used interchangeably with “variety” and “strain.”

Determinate: A term used to classify tomatoes that centers on the length of time the plant produces fruit during the season. Determinate tomatoes produce for a couple of weeks and then production fades out. When terminal buds set fruit, plant growth stops.

Globe tomato: A term used to classify tomatoes that centers on the size and shape of the fruit. A globe tomato is uniformly round. It is sometimes called a “slicing” tomato. Globes are the most commercially cultivated tomatoes.

Harden off: Gradually acclimating tomato seedlings to outdoor temperatures, sunlight, and wind to prepare them to be set out in the garden.

Heirlooms: Tomato varieties that have been reproduced for generations without cross-breeding. Heirlooms are classified into four categories:

• Commercial — open-pollinated varieties introduced before 1940.

• Family — seeds that have been passed down for several generations through a family.

• Created — two crossed varieties bred multiple times to eliminate undesirable characteristics and stabilize desired characteristics.

• Mystery — varieties that are a product of natural cross-pollination with other heirloom varieties.

Hybrids: Varieties that deliberately bred as a cross between two different varieties, most often to cultivate specific characteristics.

F1 hybrid is the first generation seeds that come from plants with two specific parents. F2 hybrid is seeds that come from crossing two F1 hybrid parents.

Indeterminate: a term used to classify tomatoes that centers on the length of time the plant produces fruit during the season. Indeterminate tomatoes produce fruit throughout the season, often until frost. They never set terminal flower clusters, only lateral ones, and continue indefinitely to grow taller.

Locules: Small cavities or chambers within the tomato that hold the seeds within a jelly-like substance. Some tomatoes are bi-locular (2 chambers). Many are multi-locular (many chambers – as many as 10).

Lycopersicon esculentum: The tomato’s botanical classification (genus and species).

Maturity: the number of days from transplanting seedling in the garden to its first mature fruit. Early-season varieties mature in 55 to 68 days; midseason varieties in 69 to 79 days; late-season varieties in 80 days or more.

Open-pollinated (OP): A tomato variety that has been pollinated by its own variety.

Plum tomato: A term used to classify tomatoes that centers on the size and shape of the fruit. Plum tomatoes are medium- to small-sized, oval or cylindrical in shape, thick-walled and have fewer seed compartments. Plum tomatoes are sometimes called paste tomatoes or Roma tomatoes.

Pollination: The process in which pollen is transferred in tomato plants for fertilization. Pollen grains are released by a flower’s anther and fall to the stigma, usually within the same flower.

Slicing tomato: A term used to classify tomatoes that centers on the size and shape of the fruit. A slicing tomato is uniformly round. It is also called a “globe” tomato. They are the most commercially cultivated tomatoes.

Strain: A specific tomato type. The term “strain” is often used interchangeably with “variety” and “cultivar.”

Variety: A specific tomato type. The term “variety” is often used interchangeably with “strain” and “cultivar.”