СТВОЛ _|_ TRUNK / STVOL [stvoɫ]
Hint with an alternative definition: It is an alive stock of a tree, full of leaves, with a vault (tree hollow) and strong will not to fall (by an ax or without roots).
Hint with composition: stalk, stem + volume = a big trunk
Hint with transformations: brainstem > brain trunk or tRUnk (brain stem in Russian)
Hints with translation + consonant words (by sounds or letters): it stands like a solo tower with lofts (crown) or a tall wall (row of stakes) without faults
Mental visualization: sawn trunk = C (trunk cut) + ТВОЛ (trunk: “Т” — branch, “В” — fruits, “О” — another cut, “Л” — saw)