To do with the small tubes that carry liquid inside a living body — blood and lymph in animals, water and food in plants.

To do with跟...有關 the small tubes小管子 that carry liquid inside a living body負責運送生物體內液體 — blood and lymph in animals動物體內是血液和淋巴, water and food in plants植物體內是水和養分。

In medicine you meet it constantly: 'vascular disease' is disease of the blood vessels, 'a vascular surgeon' operates on arteries and veins, and 'cardiovascular' means heart and blood vessels together (that is the word on the exercise machine at the gym). In biology, 'vascular plants' are plants with proper tubes inside — trees, grass, ferns — as opposed to mosses, which have none.

In medicine you meet it constantly在醫學裡你會常常碰到它: 'vascular disease' is disease of the blood vessels 'vascular disease'(血管疾病)指的是血管的疾病, 'a vascular surgeon' operates on arteries and veins 'a vascular surgeon'(血管外科醫師)專門處理動脈和靜脈, and 'cardiovascular' means heart and blood vessels together 'cardiovascular'(心血管的)指的是心臟和血管一起 (that is the word on the exercise machine at the gym就是健身房運動器材上會看到的那個詞)。In biology在生物學裡, 'vascular plants' are plants with proper tubes inside 'vascular plants'(維管束植物)是體內有真正管子的植物 — trees, grass, ferns樹、草、蕨類 — as opposed to mosses, which have none跟完全沒有這種構造的苔蘚相對。

There is also a useful everyday-ish use for tissue that has a lot of blood in it: skin that bleeds easily is 'highly vascular'.

There is also a useful everyday-ish use還有一個實用、比較口語一點的用法 for tissue that has a lot of blood in it用在血流很豐富的組織上: skin that bleeds easily is 'highly vascular'容易流血的皮膚就是'highly vascular'(血管很豐富)。

This is a technical adjective; it belongs to doctors, nurses, and science books, and it has no casual form. Ordinary people talking about the same thing say 'blood vessels', 'circulation', or 'blood flow' — a doctor may say 'poor vascular supply' to a colleague and 'not enough blood is getting there' to the patient.

This is a technical adjective這是個技術性的形容詞; it belongs to doctors, nurses, and science books屬於醫生、護理師、和科學書籍的用語, and it has no casual form沒有口語版本。Ordinary people talking about the same thing say一般人講同樣的事情會說 'blood vessels' 'blood vessels'(血管), 'circulation' 'circulation'(循環), or 'blood flow'或'blood flow'(血流) — a doctor may say 'poor vascular supply' to a colleague醫生對同事可能會說'poor vascular supply'(血管供應不良) and 'not enough blood is getting there' to the patient對病人則會說「這裡血液供應不夠」。

Note that it describes the tubes, not what flows in them: 'vascular' is about the pipes.

Note that it describes the tubes要注意它形容的是管子本身, not what flows in them不是裡面流的東西: 'vascular' is about the pipes 'vascular'講的是「管路」。