基部|きぶkibu[1]atamadaka (head-high)

1. no-adjectivebase; foundation

• Synonym基底きていWrittenWritten and academic; the most fundamental basis of something or the bottom face of a solid, also a math term. 「基部」 refers to the root-end section of a part.
• Synonym土台どだいNeutralThe load-bearing base of a building, also figurative for foundations, and an adverb meaning 'by nature'; 「基部」 is the root-end section of the object itself.
• SynonymベースNeutralLoanword for basis, standard, base and the like, mostly abstract or everyday; for the root-end part of an object use 「基部」.
• Related基礎きそNeutralThe common word for building foundations or the essentials something rests on; 「基部」 names the root-end section of an object or organ.
• Related根底こんていWrittenWritten and abstract: the deepest root of an idea or thing, as in 「根底から覆す」; 「基部」 is a concrete section of something.
• Related根っこねっこCasualColloquial; a plant's roots or the essence of a matter, also the base part; 「基部」 is technical, for organs and components.
• Related礎いしずえWrittenWritten; the cornerstone set under pillars, mostly figurative for what underpins a nation or enterprise, as in 「国の礎」 — unlike the concrete section 「基部」 names.
• Related礎石そせきWrittenWritten; a building's foundation stone, also figurative for the basis of something; 「基部」 is the root-end section and never figurative.
• Related基本きほんNeutralFully abstract: the basic principles behind judgment and action, never a physical part; it meets 「基部」 only in the 'basis' sense.
• Related麓ふもとNeutralTerrain only: the area at the foot of a mountain or hill; 「基部」 covers the root end of all kinds of objects and organs.
• Related下地したじNeutralGroundwork: an undercoat or primer, or basic training and aptitude, as in 「下地がある」; it never names a root-end section.
• Related基盤きばんNeutralElectronics term for circuit boards and substrates; unrelated to the root/base-of-organ sense of 「基部」.
• Related底辺ていへんNeutralThe base of a polygon or the bottom of society, also a supporting basis; 「基部」 is the root-end part and says nothing about social class.
• Antonym先端せんたんNeutralThe pointed tip of something long, also the cutting edge — the opposite end from the root-side 「基部」.
• Antonym末端まったんNeutralThe far end of an object or the grassroots of an organization; on something long it sits at the opposite end from the root-side 「基部」.
• Antonym頂部WrittenWritten/formal; the topmost part of an object, directly above the bottom or root end where 「基部」 sits.

Use 「基部」 for the root-end section of an object or organ — a technical choice. For plants or pillars in everyday speech say 「根元」 (or colloquial 「根っこ」); for building and abstract foundations use 「基礎」 or 「土台」; for the foot of a mountain, 「麓」. Written alternatives include 「基底」「根底」「礎」「礎石」; 「ベース」 and 「基本」 are abstract; 「下地」 is groundwork, 「基板」 a circuit board, 「底辺」 a polygon's base or the social bottom. The opposites are 「先端」, 「頂部」 and 「末端」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 基礎きそとなる部分ぶぶん
2. 根本こんぽんの部位ぶい。