The 180 degree turned shape of #17, pointing down symbolizing bellow .
The left side line is longer than the right, for distinguishing it from 23 easier.
. . . .
( If you don't understand how to read this page, see here first )

the hand-shape-sign:
point down with the extended thumb (親指で下を指す)
the hand-movement-sign:
moving the other signed hand a fist width downward from the original position

name: [so] (so, sound of soap ) ( ソ )

ASCII: t (as the partner base of 17 (T))

phonetic value: [function]

definition (single): below, under, lower direction (下)


(vi.) become under (下になる)
(vt.) take something under (下にする)

main images in base overlays:

1) Related to 'lower/under/below direction' (下、下方にかかわる)
2) Related to 'downward or moving/getting down' (下向き・下降に関連)
3) To form a pronoun pointing a very close particular thing (目の前のものを指す代名詞)
4) Related to "psychologically lower/under/downward" (心理的な低さに関連)
5) To form 'condescend' in the honorific (謙譲語の構成にかかわる)
6) Related to 'quality low' (質的な低さにかかわる)
7) Related to south (南に関係)

examples of base overlay:

Related to 'lower/under/below direction' (下、下方にかかわる)

{18,28(surface)}: the under/wrong side surface (the opposite side of top) (下側)
{13(the same level),18}: the same or lower, lower than... (〜以下)
{{10,13}(level),18}: lower level/ lower lank (than standard) (下級)
{18,16(part)}: under part (下部)
{11(limit),18}: the low/under limit (下限)
{03(line),18}: under line (アンダーライン)
{17(up),18}: up and down (上下)
{17,18,23(change)}: reverse up and down: upside down (上下逆さ)
{17,18,23,54(being)}: a hand-stand or to be standing in upside-down (逆立ち)
{42(flowing ),18}: down stream (下流)
{60(true),18}: right beneath/under (真下)
{61(front),18}: the under front (前下方)
{62(back),18}: the under back (後ろ下方)
{18,{11,12}(limitation)}: the lowest ( for any images) (最低)
{18,{01,10}(position)}: : a lower, a below position ( for anything) (下位置)
{18,37(nature)}: underground (地下)
{18,37,59(water)}: underground water (地下水)
{{18,37,20(out),10(place)}: Hell (地獄)
{{11,28}(wall),18}: floor (床)
{{10,48}(building),18}: foundation (of a building) (建物の基礎)
{18,48(cover)}: protected situation, protect (vt. with #ge) (保護されている、E動詞:保護する)
{{02,14}(hair),{04,39}(mouth),18(under)}: beard (あごひげ)
{{15,33,66}face,18(lower part)}: chin (あご先)
{44the sun,18 under (the ground),36 time}: midnight (深夜)
{70 duration including }: night-time (夜間)
Related to 'downward or moving/getting down' (下向き・下降に関連)

{07(much),18} : deep( downward) (底深い)
{08(little),18}: shallow( downward) (底浅い)
{{07,08}(degree),18} : depth (深さ)
{18( downward),51(power)}: weight (重さ)
{18,51,07(much)}: heavy (as weight) (重い)
{18,51,08(little)}: light( as weight) (軽い)
{18,21(heading)}: downward, heading down (下向/下降)
{70(space),18}: sinking sink( vi. with gd) (沈、D動詞:沈む)
{01 (the point),18}: the bottom tip (底)
{18,58( 'hung' in this case by the shape )}: hanging down, hang down( v. with gd) (吊り下げ)
{18,66( plant )}: drooping, droop (vi. with gd: for plants), dejected( for human) (しおれた、D動詞:うなだれる)
{18(down),{36(time),37(nature)}(season)}: the season while leaves fall 'down': fall (season)/autumn (秋)
{{33,44}(the sun).18(down)}: sunset (日の入り)
{17(up),18(down),10(place),14(way)}: elevator (エレベーター)
{18,{41(move),68}(emotion)}: cooling down one's emotion ((気持ちの)鎮静)
{18,43(rolled)}: winding down, wind down( v. with gd) (巻き下ろす(伸ばす))
{18,41(move)}: going down, climb down (くだる、下降する)
{18,{41,43}(reptile)}: crawling down, creep down (vi. with gd) (D動詞:這い下りる)
{02,18}: (hieroglyphic) like an arrow, going down with the gravity:
falling, fall (vi. with gd), drop (vt. with ge);
This hand-sign is pushing down long (for 18) by the 02(the straight up index finger) signed hand.(落下)
{{02,18}drop down,68}: discouragement, discouraged, be disappointed (vi. with gd),
discourage (vt. with ge) (落胆)
{67life,18(downward)}: drooped, dejected, weakened (衰え、弱った)
To form a pronoun pointing a very close particular thing (目の前のものを指す代名詞 )

{18,34(pronoun)}: this (これ)
{18,34,27(plural)} : these ( pointing things in front of eyes) (これら)
{18,34,10(place)}: this place (ここ)
{{34,18}(this),21(heading)}: come (from another place to here) (来る)
{55(request) for{34,18,21}come}: asking to come this way/call (n./v. with gd) (呼び寄せ、呼ぶ)
Related to "psychologically lower/under/downward"(心理的な低さに関連 )

{{21,18}(downward), 68(heart)}: melancholy, depress (v. with gd) (憂鬱)
{18,{41,68}impression}: worry (心配)
{{34,39}(eyes),18,68}: disdain, scorn, looking down on (v. with gd) (軽蔑)
{18,15(recognition)}: bad criticism, be bad received (passive v. with {gd, 47}) (低評)
{18,{15(recognition),68(heart)}consciousness}: modesty, modest (v. with gd) (謙遜)
{18 from 12(friction)}: frustration, frustrate (vi. with gd) (挫折)
{18(related to 'deep' ocean color),{33,23}(color)}: indigo dark blue (藍いろ)

*Before #18 base was used for lower generations and relatives, but the usage has been canceled, taking the meanings as befor-time generation/relatives. (September, 2006) See #67-base overlays for relatives.
To form 'condescend' in the honorific (謙譲語の構成にかかわる )

{10(place),18}: Putting this in front of a verb to show the talker's being humble
in the honorific in ancient culture.
Related to 'quality low' ( included subjective view points) (質的な低さに関わって)

{49(quality),18}: low quality (低質)
{49,18,38(made)}: deterioration (品質低下)
{18,50(goods)}: a coarse article (粗末な品)
{18,39(sense)}: vulgar (下品)
{18,46(function)}: inferior (劣った)
{18,23(change)}: changing for the worse, make worse( vt. with ge) (悪化)
{18,{10,65}(society)}: low society (when it has ranks) (低層社会)
Related to south (since traditionally south is mostly positioned down in a map) (南に関係)

{18,33(globe)}: south, southern (南)
{{18,33} south,{10,12} pole}: the south pole (南極)
{{07,08} degree,{18,33} southern} : (a) southern latitude (南緯)
{{18,33},32(unit)}: the degree-unit of southern latitude,
as (southern latitude thirty three degrees) (南緯の緯度)

. . .