the hand-shape-sign:
pointing inward (one's own body direction) with the extended thumb. (肩前、親指で内側を指す)
the hand-movement-sign:
moving the other signed hand a fist width inward from the original position. (拳幅内側に動かす)

name: (soo sound of soot) ( ス )

ASCII: < (looks similar)

phonetic: [function]:

To change the place of articulation one step inward than the original,
the diacritic for Retracted; also additionally work for pitch with #17or and #18 (see here for the examples)
(音韻記号に重ねて、その調音の場所を内側にずらすと示す。
また17,18の音程を示す記号の補足にも使用)( 表音システム参照)

definition (single): inside, in (this itself is not a preposition; just as the image) (内)

verb:
vi. enter, be inside (入る)
vt. put (something) in (入れる)

special usage compounding with verb symbol:
{gd.19}: (pointing original direction of the writing) the past tense d-verb symbol;
became ../ did .. (過去Ｄ動詞符；〜になった、〜した)
{ge.19}: the past tense e-verb symbol (made someone to do ..) (過去Ｅ動詞符；〜させた)

main image (in C-c):

1) Related to in/ inside/ inner/ internal/self (内がわや自身に関連)
2) Related to inward or oneself (内向きに関連)
3) To symbolize one side of bipolar concepts as
the left, west, female, past tense (working with 20 for the opposite side)
(男女・左右・東西など、対ある概念の一方ずつを#20と分かつ)

examples of C-c:

Related to 'in/ inside/ inner/ internal/self'( since the sign points to inward/ oneself )
(手話記号が内または自分の方向を指すので内・自分自身に関連して)

{19,28( surface )}: the inner surface (内側の面)
{{11,28}( wall ),19}: interior wall (内壁)
{13( the same level ),19}: the same or inner, inner than... (より内部)
{19,16( part )}: inner part (内の部分)
{11( limit ),19}: a scope, a range, within (with gc, as a preposition) (領域内)
{03( line ),19}: inside of line (線内)
{19,20( out )}: in and out (内外)
{19,20,23( change )}: reverse of in and out: inside out (裏返し)
{19,01}: (pointing inner way): oneself (as a fundamental) (自身)
{33,{01(point),19(in)}(oneself)}: score point (得点)
{19,{01,10}(position)}: one's own side (自分側)
{{01,19}(self),{48,51}(support)}: independence/ self-help (自立)
{19.01.20}(as the combination of 'self' and 'other'{20,01} }: each other (互い)
{{46,63,48}(grasp),{01,19,20}}: handshake (v. with #gd) (握手)
{10( place ),19}: inside (内側)
{{10,48}( building ),19}: interior (室内)
{19,58( possibility )}: potential (潜在的な可能性)
{19,48(cover)}: secret (秘密)
{14(go through),19}: betrayal, betray( v. with gd) (内通)
{19,25(join )}: included, include (vt. with ge) (含んだ、E動詞：含める)
{19(in),{36(time),37(nature)}(season)}: the season while most people and animals keep 'indoor': winter (冬)
{19,{15(recognition),68(heart)}consciousness}: subconscious (潜在意識)

Related to 'inward' (内向きの方向に関連)

{07(much),19} : (inward) deep (奥深い)
{08(little) ,19}: (inward) shallow (内向きに浅い)
{{07,08}(degree),19} : (inward) depth (奥深さ)
{19,41(move )}: enter (入る)
{19,{41,43}(reptile)}: crawling in, creep in (vi. with gd) (這い入る)
{06(resistance),19}: locked out situation (入るのが禁止の状態)
{19,51(power)}: input (入力)
{07,{19,51}}: much input (入力大)
{08,{19,51}}: little input (入力少)
{19,21(heading direction)}: inward, introversion, turn inward/introvert (vi. with gd/vt. with ge) (内向き)
{19,21,49(nature, personality )}: introverted nature (内向性)
{19(in),21(heading),51}: centripetal force (求心力)
{19(in),{49,68}}: private, withdrawn (内気な)
(19,12( friction)}: blame, take the blame for... ( v. with gd, {gc,22}), accuse (vt. with ge) (責め、とがめ)
{19,{41(move),68}( emotion )}: impression, be impressed( vi. with gd), impress (vt. with ge) (印象)
{19,43( rolled)}: involved, involve( vt. with ge) (Ｄ動詞：巻き込まれる、Ｅ動詞：巻き込む)
{19,47( container/a part of 'room')}: entrance (entry), accommodate, put in (v. with ge) (入会・入場、Ｅ動詞：収容する)
{{47,41}viacle, 19,20(in-out), 10place}: bus/train station
{19,{33,23}(color)}: purple (紫)
{19,{34,38}(money)}: revenue, income (収入)
{19,{34,38}(money),47(vessel)}: deposit, saving money (預金)
{19,20(out),{34,38}money,47}: banking (銀行業務)
{44 the sun,19 in (gets in under the horizon), 36time}: sunset-time (日没どき)
{70 duration including }: evening (夕方)
{61 after }}: dusk/evening after sunset (夕暮れ)

{19,34( pronoun )}: she, her (彼女)
{19,67( life )}: female(s)/woman (fundamental character) (女・雌)
{19,67,27(plural)}: women/females (only for plural) (女たち)
{61(later),19,67}: daughter (息女)
{(62(earlier),67}( parent ),19}: mother (母)
{62,67,19,n2}: 2 generation upper mother: grandmother (祖母)
{62,67,19,n3}: great grandmother (曾祖母)
{{67,13(the same level)} ( sibling: fundamental character ),19}: sister (姉・妹)
{67,13,19,n2}: secondly far female in the same generation: female cousin (従姉妹)
{67,13,19,n3}: second female cousin (また従姉妹)
{62,67,19,13}: the same level of a parent and female: aunt (叔母・伯母)
When you feel the above characters look too mess, you can put the numbers , in front separately:
as = (見にくい場合には、左のように分離も可能)
{19(female),17(for a term of respect),65(human)}: Ms. or lady (女性の敬称)
{19,17,65,27(plural)}: ladies (ご婦人方)
{19,20(male),17,65}: Mr. and Mrs. (紳士淑女)
{19,20,17,65,27}: ladies and gentlemen (紳士淑女かたがた)
{19,66}: female of plant (when differs are) (雌株の植物)

{02(vertical line),19}: the left (fundamental character by the shape) (左)
{02,19,20(out)}: the left and the right: both, both sides (左右)
{33(globe),19}: the west (西)
{33,19,{07,08}(degree)}: the west longitude (西経)
: {33,19,32(unit of degree)} 125.42: longitude 125.42 degrees West (西経125.42度)
{33,19,21(heading)}: toward the west (西向き)

As past and past tense(過去に関連)

{19,36(time)}: past (since #19 points the opposite direction where the writing goes to) (過去)
{{19,36}(past),50}: antique (骨董)
{gd,19}, {ge,19}: past tense verb symbols (動詞符の過去)